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Volume 76, 1946-47
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On the Circulatory System of Leiopelma hochstetteri with Particular Reference to the Posterior Cardinal Veins and to the Blood-vessels of the Kidneys.

[Read before the Auckland Branch July 17, 1946; received by Editor, July 29, 1946; issued separately, September, 1947.]

Introduction.

Although the arterial circulation of Leiopelma hochstetteri conforms essentially to the typical Anuran plan, the venous system is peculiar in possessing well-developed right and left postcardinal veins, the posterior extremities of which are in communication, either directly or indirectly, with the postcaval vein. Anteriorly, each post-cardinal vein unites with the corresponding internal jugular vein to form a wide, transversely placed ductus Cuvieri which enters the lateral aspect of the sinus venosus. Thus, an innominate vein or distal portion of the ductus Cuvieri (O'Donoghue, 1931), as typified in Rana, is not present in Leiopelma, and the main vessels of the precaval system retain essentially their embryonic relationships.

The circulatory system of Leiopelma exhibits also a number of abnormalities and variations. These, as might be expected from consideration of other vertebrate types, are especially abundant in the venous system, but the arterial blood supply to the kidneys has been found to be abnormal in a number of instances. As far as possible, in the following description, an attempt has been made to conform to O'Donoghue's definition (1931) of the terms “variation” and “abnormality,” but this has not been practicable in all cases. In connection with the veins draining the kidneys, for instance, a number of examples have been described to illustrate cases of what are, strictly speaking, abnormalities. However, the incidence of these is so great that it has so far been impossible to decide exactly what is the normal condition of these vessels in Leiopelma, and for the present purpose the examples quoted are referred to simply as individual variations.

Materials and Method.

The description given below is based entirely on dissection of injected specimens of Leiopelma, most of which were sexually mature. Latex, the medium used throughout the work, was injected through the ventricle or the left auricle of freshly killed animals. The advantages of latex over the older gelatin or starch injection masses was found to be very great. Penetration in most cases was excellent, while the added elasticity of the blood vessels was of tremendous advantage in dissection.

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The Arterial System.

I.—The Carotid Arch.

For the purpose of the following description, the detailed distribution of the vessels of the brain will not be considered. The distribution of the main vessels arising from the carotid arch in Leiopelma differs little from that already described in detail for Rana esculenta (Ecker, 1889). General characteristic differences may be summarised as follows:—

(a)

A slender cutaneous artery arises a short distance beyond the point of origin of the lingual or external carotid artery and passes back to supply the cutaneous capillaries of the ventral surface of the body at approximately shoulder level. (Text Figure I.)

Picture icon

Text Fig. 1.—The Carotid Artery and its branches. Ventral aspect. (Tongue and mucous membrane of palate have been removed from right half of head.) a.p.—Anterior branch of palatine artery. b.p.p.—Branch of posterior palatine artery. c.a.—Carotid artery. c.ar.—Carotid arch. c.b.l.—Cutaneous branch of lingual artery. e.g.—Carotid gland. d.b.l.—Deep branch of lingual artery. i.c.—Internal carotid artery. 1.—Lingual or external carotid artery. m.m.p.—Mucous membrane of palate deflected forward. o.—Orbit. p.a.—Palatine artery. ps.—Parasphenoid. s.b.l.—Superficial branch of lingual artery. t.—Tongue. t.a—Truncus arteriosus.

(b)

A single palatine artery arises from the carotid artery immediately before the latter crosses the posterior border of the orbit. This palatine trunk supplies a small vessel to the underlying mucous membrane before dividing into two ultimate branches which correspond in function to the anterior and posterior palatine arteries of Rana.

(c)

The anterior spinal artery communicates with the occipito-vertebral artery on each side by a single ventral or spinal branch arising from the latter.

II.—The Systemic Arch. (Plate 43.)

From before backward, the branches arising from the left systemic arch before its junction with the right arch to form the dorsal aorta are as follows:—

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(i)

An oesophageal artery.

(ii)

A gastric artery, passing to the stomach.

(iii)

The occipito-vertebral artery, passing to the dorsal region of the body.

(iv)

The subclavian artery, supplying the shoulder and arm.

(v)

Three dorso-lumbar arteries, supplying the muscles of the body wall.

(vi)

Three branches, passing to the oviduct, kidneys and fat-body of the same side.

The branches of the right systemic arch are symmetrical with those of the left, except for the lack of oesophageal and gastric arteries on the right side.

The dorsal aorta gives rise to a further series of branches:

(1)

The coeliaco-mesenteric artery, supplying the alimentary canal and its associated glands.

(2)

A variable number of urinogenital arteries, supplying the kidneys, gonads and oviducts.

(3)

Several pairs of small dorso-lumbar arteries, passing to the dorsal body wall.

(4)

An anterior haemorrhoidal artery, arising either before or behind the last pair of renal arteries and passing to the large intestine.

(5)

A posterior haemorrhoidal artery, supplying the large intestine and the bladder.

(6)

Two iliac arteries, formed by the ultimate bifurcation of the dorsal aorta and passing to the hind limbs.

The occipito-vertebral artery, which arises opposite the level of the shoulder, passes inward and upward towards the vertebral column. Close to the latter, a small central branch comes off the main trunk and passes inward to the ventral surface of the spinal cord, where it unites with the anterior spinal artery. The main artery continues upward to the dorsal level of the vertebral column, after which it passes forward and outward as the occipital artery until it reaches the inner posterior border of the orbit. Before descending to supply the lining of the inner wall of the orbit, the occipital artery gives off two branches, one of which supplies the skin covering the outer wall of the orbital region, while the other passes downward to the roof of the mouth.

In Leiopelma, a vessel corresponding fully to the vertebral artery of Rana does not exist, and the only representative of the “rami spinales” (Ecker, 1864) of the latter is the small ventral vessel which unites with the anterior spinal artery. The functions of the vertebral artery appear to be served in Leiopelma by the dorso-lumbar arteries arising from the systemic arch and renal arteries and supplying the vertebral column and muscles surrounding it. A vertebral artery is lacking also in Hyla aurea. (Marriner, 1905.)

The subclavian artery conforms largely in its distribution to the same vessel in Rana, but exhibits minor differences in the positions of the finer branches supplying skin and muscles. Leiopelma exhibits no trace of the costo-cervical branch of the subclavian artery, but its function is carried out by means of the three pairs of dorso-

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lumbar arteries arising from the systemic arches. The latter run between the transverse processes of the second to the fifth vertebrae and pass through the intervertebral foramina to supply the vertebral canal. In addition, they feed the surrounding muscles.

An interesting feature shown in Leiopelma is the presence of three oviducal and renal arteries arising from the backwardly-curving region of each systemic arch. (Plate 42.) The two anterior branches are short vessels which pass directly outward and backward to the anterior region of the corresponding oviduct. Shortly before the dorsal aorta is formed, a third artery takes its origin. This, after branching to supply the fat-body, passes diagonally back over the antero-ventral surface of the kidney, until it reaches the outer border of this organ. It then turns backward and runs toward the posterior end of the kidney, sending out, more or less at right angles, several arteries which ramify over the surface of the corresponding oviduct.

The Dorsal Aorta.

1.—The Coeliaco-mesenteric Trunk.

The coeliaco-mesenteric trunk gives rise to the usual two branches:

(a)

A gastric artery.

(b)

A mesenteric artery.

The distribution of the branches arising from these main vessels is shown in Plate 41.

2.—The Urinogenital Arteries. (Plate 42.)

The arteries from the dorsal aorta to supply the kidneys and reproductive organs, although much more regularly arranged than the efferent renal veins, are rarely symmetrically placed. Most commonly, there are four pairs of urinogenital arteries, with the successive pairs comparatively widely spaced. Sometimes, the members of the two middle pairs are symmetrical, while those of the anterior and posterior pairs show variations in their positions. In other, more abnormal individuals, the arteries passing to one kidney may show no correspondence either in number or arrangement with those of the opposite side. In extreme cases two arteries have been observed on one side, and a single, large artery on the other. Where four pairs of renal arteries are present, it is generally found that each of the first two vessels on each side passes to the inner border of the corresponding kidney and divides into two, one branch passing into the substance of the kidney, while the other passes to the ovary of the same side. The third artery, in addition to supplying the kidney and the gonad, produces an extra branch which passes over the ventral surface of the kidney to carry blood to the portion of the oviduct more posterior to that supplied by the oviducal branch from the systemic arch. The fourth renal artery also sends a branch to the oviduct, but does not always supply the ovary. In the males of Leiopelma, the derivation of the spermatic arteries appears to correspond to that of the ovarian arteries.

The Iliac Arteries.

The dorsal aorta bifurcates near the middle of the urostyle to

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form the iliac arteries, each of which passes obliquely outward and backward to the base of the corresponding thigh to become continuous with the sciatic artery. The course of the latter is essentially similar to that in Rana, and peroneal and tibial arteries are formed at the knee in similar fashion. As the tibio-fibula is not perforated in Leiopelma, however, the main tibial artery curves around the bone instead of passing through it as in Rana.

III.—The Pulmo-cutaneous Arch.

Little deviation from the typical Anúran condition is seen in the vessels of the pulmo-cutaneous arch. The pulmonary artery is approximately equal in diameter to the cutaneous trunk, but the extensive plexus of cutaneous capillaries leaves little doubt as to the importance of the respiratory function of the skin, notwithstanding the semi-terrestrial habitat of Leiopelma.

The Venous System.

I.—The Precaval System. (Plate 45.)

The Internal Jugular Vein.

The internal jugular vein is formed by the confluence of three main vessels:

(a)

A vein formed by the confluence of factors from the brain itself.

(b)

A vessel which drains the skin and muscles of the back of the shoulder and head.

(c)

A vessel draining the tissues of the eyeball, eye-muscles, mucous membrane of the palate, and part of the nasal cavity.

A number of small vessels drain the ventral regions of the eye-ball and eye-muscles. Into the vein formed by their confluence, open separate vessels from the dorsal aspect of the eyeball and the skin above it, as well as a tributary from the nasal cavity. Slightly more posteriorly, a vessel draining a large area of the mucous membrane of the palate joins the main vein, after which the latter curves backward and outward around the outer side of the auditory capsule and passes toward the angle of the jaw. Here, it receives a tributary which drains the skin and muscles of the back of the shoulder. From this point, the main trunk curves inward and back, uniting with the vessel from the brain, to form the internal jugular vein, a stout trunk which runs back for a short distance before uniting with the postcardinal vein. The ductus Cuvieri thus formed passes transversely across the body to enter the sinus venosus.

The External Jugular Vein. (Plate 45.)

The external jugular vein is formed, as in Rana, by confluence of lingual and mandibular veins. The mandibular vein takes its origin in the lining of the anterior ventral region of the maxilla, and runs backward along the whole length of the bone. A number of small tributaries enter it on either side. At the posterior extremity of the maxilla, the mandibular vein curves slightly inward and divides into two channels, which pass transversely across the body. The anterior channel is joined by a vein draining the anterior of the

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shoulder, while the other divides again into two. Shortly before the point of union with the lingual vein, all three vessels unite again to form a single vein, which, after joining with the lingual vein, curves back close to the heart, to enter the ductus Cuvieri. As it passes close to the heart, the left external jugular vein receives from the truncus arteriosus a small vessel which apparently corresponds to the vena bulbi anterior of Rana. The lingual vein is formed by a number of small vessels draining the tongue and hyoid. It passes directly back to unite with the mandibular vein.

The Musculo-cutaneous Vein.

The musculo-cutaneous vein enters the ductus Cuvieri opposite the point of entrance of the external jugular vein. It is not altogether comparable to the vessel of the same name in Rana, being only a slender vein formed almost entirely from the confluence of widely ramifying cutaneous tributaries draining the ventral surface of the abdomen. A few small tributaries from the ventral body wall enter it as it passes to the ductus Cuvieri.

The Postcardinal Veins. (Plates 44 and 45.)

Each postcardinal vein is a moderately stout vessel which, at its posterior extremity, is united either with the postcaval vein itself or with one of the main efferent renal veins which form the postcaval vein. From this posterior point of union, each postcardinal curves slightly outward to reach the corresponding kidney, and is closely applied to the inner edge of the anterior third of that organ. This condition is undoubtedly correlated with the fact that the relative length of the kidneys in Leiopelma is rivalled among Amphibia only by that found in Ascaphus and the caecilians.

From the anterior extremity of the kidney, the postcardinal vein passes forward almost to the level of the arm, lying in close proximity to the lateral edge of the systemic arch. A short distance behind the level of the subclavian artery, the postcardinal vein curves outward towards the arm, the exact degree and position of the curvature varying with the individual. After passing forward for a short distance, the vein turns inward again and passes across to the heart, forming by its union with the main veins from the anterior region of the body, a wide channel, the ductus Cuvieri, opening into the lateral aspect of the sinus venosus.

The postcardinal vein receives a number of tributaries, some of which are of major importance, while others are merely small vessels draining muscles.

(i)

Shortly after the postcardinal vein leaves the kidney, it is joined on its outer side by a small vein draining the extreme anterior region of the oviduct.

(ii)

Slightly further forward, one or two oesophageal veins pass to the inner side of the left postcardinal vein.

(iii)

Several very small veins draining the more anterior muscles of the dorsal body wall enter the main vessel, either during its longitudinal course, or after it has begun to curve out towards the arm. Further forward, the postcardinal vein receives several important vessels belonging to the precaval system.

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(iv)

Opposite the arm and anterior to the subclavian artery, the brachial vein, which receives blood drained from the forelimb and hand, joins the postcardinal vein.

(v)

A short distance beyond the point where the postcardinal vein turns toward the heart, it unites with the stout trunk of the internal jugular vein.

The Postcaval Vein.

From its origin between the more anterior region of the kidneys, the stout, median postcaval vein passes forward, dorsal to the liver, to open into the posterior region of the sinus venosus.

The Hepatic Portal System. (Plates 41 and 45.)

As in Rana, the hepatic portal system comprises two main trunks, the anterior abdominal or epigastric vein, which drains the ventral abdominal wall, hind limbs and part of the pelvic region, and the hepatic portal vein proper, which drains the alimentary canal and the spleen. The tributaries of the hepatic portal vein are illustrated in Plate 41.

The Renal Portal System.

In general arrangement, the veins of the hind limb are similar to those of Rana. Immediately beyond its point of entrance to the pelvis, however, the femoral vein unites with the sciatic vein to form a common trunk which may be regarded as an external iliac vein, although it is not strictly homologous with the vein of the same name in Rana. After passing forward for a short distance, this vessel receives a small tributary from the dorsal body wall, and soon afterwards bifurcates to form the renal portal vein and the pelvic vein. Immediately before the point of union, each pelvic vein may receive a vesical tributary from the antero-lateral region of the bladder, or a single vesical trunk may enter either one of the pelvic veins. In the latter case, a small connecting vein usually unites the vesical vein with the opposite pelvic vein.

The renal portal vein passes forward to the kidney where it traverses the dorso-lateral border of almost the whole length of that organ. (Plates 44 and 45.) The tributaries of the renal portal vein consist of two series of small vessels, both variable in number. The dorso-lumbar veins are short, irregularly spaced vessels draining the dorso-lateral region of the body wall. The oviducal veins are two or more slender vessels formed by the confluence of innumerable capillaries ramifying over the surface of the oviduct. The renal portal vein, throughout its length, gives rise to a varying number of small afferent renal veins, which pass directly into the substance of the kidney to feed the widely distributed portal capillaries.

The Efferent Renal Veins. (Plate 44.)

The efferent vessels which drain the kidneys of Leiopelma are remarkably variable. Not only do they differ in number and distribution in different individuals, but they also frequently show a lack of symmetry on right and left hand sides of a given individual. While most of the blood from the kidneys is passed into a median postcaval vein, that collected from the anterior, tapering regions is

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drained forward from the kidneys by a persistent postcardinal trunk on each side.

The efferent renal veins, the factors of the renal veins proper, show extreme variation in size, number and arrangement. They cover the greater part of the ventral surface of each kidney, lying more or less transversely across the organ. As they pass in towards the middle line of the body, they widen owing to the reception of innumerable, irregular tributaries, among which considerable anastomosis is shown. The efferent venal veins draining the narrow anterior region of the kidney usually show a more regularly parallel arrangement than those from the rest of the organ. At the inner border of the kidney, the efferent renals form by their confluence the renal veins, often converging in groups to do so. Most usually, the posterior half to two-thirds of the kidney is drained by a single, very stout renal vein which takes its origin near the posterior extremity of the organ. The renal veins from each side pass forward, often closely associated with the inner borders of the kidneys and receiving many efferent renal tributaries. Before the narrow, anterior third of each kidney is reached, the main renal veins converge towards the median plane of the body, finally uniting to form the stout, median postcaval vein. Very often, the anterior, converging region of each renal vein is joined by a slender vessel which passes directly inward from the kidney and is formed by the union of several efferent renal veins anterior to those draining the main vein. In some cases, several renal veins occur on one or both sides, but these always unite in various ways to produce a single main vessel before the postcaval vein is formed. The renal veins of opposite sides may be connected by transverse vessels. In the anterior third of the kidney, the postcardinal vein itself functions as a renal vein and receives a varying number of more or less parallel efferent renal tributaries. It is closely applied to the inner border of the kidney, but posteriorly it curves away from the latter to unite either with the postcaval vein or with the main renal vessels of the same side. Thus it appears that some of the blood drained into the postcardinals reaches the liver by way of the postcaval.

Blood from the gonads and fat-bodies eventually enters either the postcaval or postcardinal veins. The spermatic or ovarian veins are slender vessels, varying in number from three to six. The fat-body is usually drained by a single small vein which passes directly into the postcardinal vein, entering the postcardinal slightly beyond its posterior point of attachment to the kidney. This is sometimes joined by one or more of the veins from the anterior of the gonad, but it is equally as common to find all the ovarian or spermatic vessels entering the corresponding main renal vein or its tributaries, sometimes uniting in pairs before doing so. In the male frog, especially, several small connecting vessels may occur which link up the veins of individual gonads as well as those of opposite sides.

A striking degree of individual variation is encountered in the arrangement of the renal veins and their tributaries, six examples of which are figured in Plate 44.

In Figure I (a), the right kidney of a female frog is shown.

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The numerous efferent renal veins and their finer tributaries are very irregularly arranged in the more posterior region of the kidney, but they are more or less parallel in the anterior portion, where they open into the postcardinal vein. The main renal vein is a large trunk, arising near the posterior margin of the kidney. It is closely attached to the inner border of the posterior third of the kidney, but beyond this point it forms a shallow loop towards the middle line of the body. Finally, it passes forward and inward to form the post-caval vein by union with the main renal vein from the opposite side. A more slender renal vein enters the postcaval vein directly, slightly behind the point of entrance of the posterior portion of the postcardinal. Four small veins from the anterior of the ovary join the vein from the fat-body to enter the postcardinal vein, while the two posterior veins from the ovary open into the main renal vein.

Figure I (b) shows the left side of the same animal. Three renal veins are present, each formed by the union of two to five smaller vessels receiving numerous irregular tributaries. The renal veins more or less parallel each other and pass forward and slightly towards the middle line. The posterior vein is by far the longest of the three, the anterior the shortest, while the middle and posterior veins are connected near their anterior extremities by a short transverse vessel. All three veins unite to form a common trunk leading to the postcaval. The anterior ovarian veins have a similar arrangement to those in Figure I (a), while the two posterior veins enter the posterior renal vein half-way along its length. The postcardinal vein is united with the anterior renal vein.

Figures 2 (a) and 2 (b) also show right and left sides of a female frog. In Figure 2 (a), the efferent renal veins are arranged in parallel series throughout the kidney, although their finer tributaries are irregular and show considerable anastomosis with each other. One main renal vein occurs, which is joined anteriorly by a smaller renal vessel. Posteriorly, a stout connecting vessel joins the main renal veins of both sides. Before the renal vein becomes continuous with the postcaval vein it is joined by the postcardinal vein. Only three ovarian veins are present, all of which make separate entrances into the main renal vein.

The condition shown in Figure 2 (b) is similar to that of the right side, except for the fact that the vein from the fat-body enters the postcardinal vein further forward and that the anterior ovarian vein enters the main renal vein after the latter has left the kidney to pass towards the middle line.

Figures 3 (a) and 3 (b) show right and left sides of a male frog. In Figure 3 (a), the main renal vein is closely attached to the kidney until it passes inward to join with the efferent renal from the opposite side, and receives approximately seven distinct, short, efferent renal vessels formed from widely ramifying tributaries. A separate but small renal vein joins the main trunk just before its entrance to the postcaval vein. The postcardinal vein enters the postcaval vein directly. The vein from the fat-body, which enters the post-cardinal, is not united with any of the four spermatic veins, all of which open separately into the short veins giving rise to the main

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renal vessel. Before reaching the kidney, the posterior spermatic vein divides into two vessels which are connected by a short transverse vein. The third spermatic vein has a circular connection uniting it with the corresponding vessel from the opposite side.

In Figure 3 (b), two main renal veins are present, but only the anterior vessel enters the postcaval directly. The anterior vein takes its origin nearly half-way up the length of the kidney and receives four main tributaries before curving inward. Immediately anterior to its junction with the postcaval, a separate small renal vein joins the latter. The posterior renal vein is formed from three comparatively stout vessels which converge towards the median line after leaving the inner border of the kidney. The main vein produced by their union passes diagonally across to unite with the main renal vein of the right side. The postcardinal vein enters the postcaval vein directly. The four spermatic veins are united in pairs to form two vessels, the anterior of which runs forward close to the tissue of the fat-body and unites with the vein from the latter before entering the postcardinal vein. The third spermatic vein is connected with that of the opposite side.

The examples quoted above are by no means isolated cases of variation. Every specimen of Leiopelma so far injected and examined has shown some peculiarities in the number and arrangement of renal veins, and it is at present impossible to state that any given condition occurs more frequently than another. It is possible, however, that detailed study of the developmental and adult stages of the urinogenital organs of Leiopelma may throw further light on the incidence and range of the abnormalities in the circulatory system.

Summary and Discussion.

1.

With respect to the arterial system, Leiopelma is typically Anuran in character and differs little except in minor details from even the more specialised types such as Rana and Hyla.

2.

Leiopelma exhibits invariably persistent and well-developed right and left postcardinal veins. Larval forms of both urodeles and frogs possess these vessels, but in the adult they are usually replaced by a median postcaval vein. Some adult urodeles retain postcardinal veins as well as a postcaval vein, and a similar condition is found in a few of the less specialised Anurans. Postcardinals are found in Ascaphus, the only other member of the Leiopelmidae (Noble, 1931), but their condition has apparently not been described in detail. Certain Discoglossid types—e.g., Bombinator igneus, B. bombinus and Discoglossus pictus possess small postcardinal veins, and these vessels have also been found occasionally in Alytes obstetricans (Howes, 1888). Xenopus laevis, among the Pipidae, and various species among the more specialised families such as the Ranidae and Bufonidae show an occasional irregular occurrence of one or both postcardinals. The main literature regarding these types is summarised by O'Donoghue (1931 and 1933). Whatever may be the reason for the occasional persistence of postcardinals in certain types, their invariable presence in Leiopelma and Ascaphus clearly supports the evidence already known regarding the primitive nature of this family.

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3.

The presence of right and left postcardinal veins, and their union anteriorly with the corresponding internal jugular veins, leads to the formation on each side of a vessel which is essentially a ductus Cuvieri. Thus the precaval system retains embryonic relationships not found in the adults of more specialised frogs.

4.

In Leiopelma, the musculo-cutaneous vein enters the ductus Cuvieri on each side directly, while the brachial vein joins the corresponding postcardinal vein. Thus Leiopelma is characterised by the absence of subclavian veins, which in Rana are formed as stout trunks by the junction of brachial and musculo-cutaneous veins.

5.

An hepatic portal system and a renal portal system are incorporated in the venous circulation of Leiopelma as in other frogs. The posterior portions of the postcardinals, however, function as efferent renal veins in the anterior region of the kidneys, and the blood thus collected enters the precaval system.

6.

In the region of the kidneys, Leiopelma shows considerable variation in the arrangement of blood vessels, the conditions of the veins being more striking than those of the arteries. There are apparently no records of similar conditions of veins in other Amphibia.

Acknowledgment.

The writers are greatly indebted to Mr. W. R. McGregor, head of the Zoology Department, Auckland University College, for suggestions and advice.

References.

Benham, W. B., 1919. On the Occurrence of Two Unusual Blood-vessels in Hyla aurea. Trans. N.Z. Inst., vol. 51, pp. 3034.

Ecker, A., 1864. Die Anatomie des Frosches (Braunschweig).

—— The Anatomy of the Frog. Translated by G. Haslam, 1889. (Oxford).

Goodrich, E. S., 1930. Studies on the Structure and Development of Vertebrates.

Howes, G. B., 1888. On the Azygos Vein in the Anurous Amphibia. Proc. Zool. Soc., p. 122.

Kellicott, W. E., 1914. Outlines of Chordate Development. (New York.)

Marriner, G., 1905. On the Anatomy of Hyla aurea. Trans. N.Z. Inst., vol. 38, pp. 447449.

Millard, Naomi, 1942. Abnormalities and Variations in the Vascular System of Xenopus laevis (Daudin). Trans. Roy. Soc. S. Africa, 29 (I), 9–28.

Noble, G. K., 1931. Biology of the Amphibia. (New York.)

O'Donoghue, C. H., 1931. Abnormalities in the Blood Vascular System of the Anura. Trans. Roy. Soc. Edin., vol. 57, p. 179.

—— 1933. Abnormalities in the Blood Vascular System of Four Fiogs. Anat. Anz., Bd. 75, s. 449.

Ortlepp, R. J., 1918. Note on the Persistence of the Right Posterior Cardinal Vein in Xenopus laevis, and its Significance. S. Afr. Journ. Sci., vol. 15, p. 413.

Parker, W. N., 1889. On the Occasional Persistence of the Left Posterior Cardinal Vein in the Frog, with Remarks on the Homologies of the Veins in the Dipnoi. Proc. Zool. Soc., pp. 145151.

Explanation of Lettering on Plates.

  • Plate 41

  • a.g.—anterior branch of gastric artery.

  • a.i.v.—anterior intestinal vein.

  • c.a.—carotid arch.

  • c.m.—coeliaco-mesenteric artery.

  • d.a.—duodenal artery.

  • d.a.o.—dorsal aorta.

  • d.v.—duodenal vein.

  • g.—gastric artery.

  • g.a.—gastric artery from left systemic arch.

  • g.v.c.—gastric vein from convex surface of stomach.

  • h.p.v.—hepatic portal vein.

  • h.v.—haemorrhoidal vein.

  • i.a.—intestinal artery.

  • i.v.—intestinal vein.

  • l.—liver.

Picture icon

Arteries and Veins of Ahmentary Canal.
(Stomach and small intestines turned towards right side of body. Main intestinal vein slightly stretched relative to its normal length.)

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Arteries to Kidneys, Ovaries and Oviducts. Ventra Aspect.
(Kidnevs shown relatively for apart; ovary of rght side removed; large intestine turned toward left side.)

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Diagram of the Arterial System.

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Veins from Kidneys and Gonads, showing Variations.
(Ventral aspect, semi-schematic; gonads displaced towards opposite sides.)
Figs. 1a and 1b.—Right and left sides of female frog, ovaries well-developed.
Figs. 2a and 2b.—Right and left sides of female frog, ovaries small.
Figs. 3a and 3b.—Right and left sides of male frog, [ unclear: ] well-developed.

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Venous System of Leiopelma
Ventral Aspect. Schematic.

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  • l.i.—large intestine.

  • l.s.—left systemic arch.

  • m.—mesenteric artery.

  • m.g.—second gastric artery.

  • m.i.v.—main intestinal vein.

  • o.a.—oesophageal artery.

  • p.—pylorus.

  • pa.—pancreas.

  • p.2.—m. petrohyoiedeus II.

  • p.d.v.—posterior duodenal vein.

  • p.g.—posterior gastric artery.

  • s.—small intestine.

  • sp.—splenic artery.

  • v.—splenic vein.

  • v.—ventricle.

  • Plate 42

  • a.h.—anterior haemorrhoidal artery.

  • a.od.—arteries to oviduct from systemic arch.

  • a.r.a.—anterior renal artery.

  • b.m.od.—branch of main artery to oviduct.

  • d.a.—dorsal aorta.

  • d.l.—dorso-lumbar artery.

  • f.b.—artery to fat-body.

  • il.—iliac artery.

  • k.—kidney.

  • l.i.—large intestine.

  • l.s.—left systemic arch.

  • m.od.—main artery to oviduct.

  • o.—ovary.

  • o.a.—ovarian artery.

  • od.—oviduct.

  • p.h.—posterior haemorrhoidal artery.

  • p.od.—posterior artery to oviduct.

  • p.r.a.—posterior renal artery.

  • ur.—urostyle.

  • v.—vertebra.

  • v.a.—vesical artery.

  • Plate 43

  • a.h.a.—anterior haemorrhoidal artery.

  • c.ar.—carotid arch.

  • c.g.—carotid gland.

  • c.m.—coeliaco-mesenteric artery.

  • cu.—cutaneous artery.

  • cu.il.—cutaneous branch of iliac artery.

  • d.a.—dorsal aorta.

  • d.l.—dorso-lumbar artery.

  • ep.—epigastric artery.

  • g.—gastric artery.

  • l.—lingual artery.

  • l.il.—left iliac artery.

  • m.—mesenteric artery.

  • o.a.—oesophageal artery.

  • o.r.—arteries to kidneys and oviducts.

  • o.v.—occipito-vertebral artery.

  • p.a.—pulmonary artery.

  • p.ar.—pulmo-cutaneous arch.

  • p.h.a.—posterior haemorrhoidal artery.

  • r.—renal arteries.

  • [ unclear: ] .—systemic arch.

  • sc.—sciatic artery.

  • s.cl.—subclavian artery.

  • v.—vesical artery.

  • v.b cu.—ventral branch of cutaneous artery.

  • Plate 44

  • a.e.r.—anterior efferent renal vein.

  • a.s.v.—anterior spermatic vein.

  • a.v.g.—anterior ovarian vein.

  • c.a.s.v.—connection between spermatic veins.

  • c.e.r.—connection between efferent renals.

  • c.s.r.—connection with right spermatic vein.

  • e.r.—main renal vein.

  • e.r.t.—efferent renal tributaries.

  • e.t.p.c.—efferent renal tributaries of postcardinal.

  • l.e.r.—efferent renal vein from left side.

  • m.a.e.r.—main anterior efferent renal vein.

  • m.e.r.—middle renal vein.

  • o.—ovary.

  • p.e.—postcardinal vein.

  • p.e.r.—posterior renal vein.

  • p.p.c.—posterior region of postcardinal.

  • p.s.v.—posterior spermatic vein.

  • pt.c.—postcaval vein.

  • p.v.g.—posterior ovarian vein.

  • r.p.v.—renal portal vein.

  • t.—testis.

  • v.f.b.—vein from fat-body.

  • v.f.b.g.—vein from fat-body and anterior of gonad.

  • Plate 45

  • a.a.—anterior abdominal vein.

  • b.v.—brachial vein.

  • c.p.IV.—choroid plexus of fourth ventricle.

  • c.t.—cutaneous tributaries.

  • c.v.—musculo-cutaneous vein.

  • d.c.—ductus Cuvieri.

  • d.m.—vein from dorsal body wall.

  • e.il.—external iliac vein.

  • e.j.v.—external jugular vein.

  • e.r.—main efferent renal vein.

  • e.t.pc.—efferent tributaries of post-cardinal vein.

  • f.—femoral vein.

  • g.b.—gall-bladder.

  • h.—hepatic vein.

  • h.p.v.—hepatic portal vein.

  • i.j.v.—internal jugular vein.

  • i.j.e.—tributaries of internal jugular from eye.

  • i.j.h.—tributaries of internal jugular from hemisphere.

  • k.—kidney.

  • l.—liver.

  • l.v.—lingual vein.

  • l.v.p.—lateral venous plexus.

  • m.v.—mandibular vein.

  • o.r.p.—veins from oviduct.

  • o.v.—oesophageal veins.

  • p.—vein from mucous membrane of palate.

  • p.c.—postcardinal vein.

  • pt.c.—postcaval vein.

  • p.v.—pelvic vein.

  • r.p.v.—renal portal vein.

  • sc.—sciatic vein.

  • v.—vesical vein.

  • v.b.a.—vena bulbi anterior.

  • v.b.h.s.—vein from back of head and shoulder.

  • v m.s.—vein from ventral region of shoulder.

  • v.o.—vein from oviduct.