far down on the anterior lip of the sucker, in front of the eyes, and probably in the 2nd annulus. It leads into the usual pharyngeal sac, which extends backwards into about somite ix. In it lies the long, muscular, club-shaped pharynx, which was somewhat displaced laterally, and undulating. It commences as a very narrow tube just behind the brain, but increases considerably in diameter as it passes backwards, so that in somite × it is four or five times its previous diameter. Opening into the posterior end is a pair of groups of salivary glands, each group consisting of a bunch of numerous large gland-cells, each of which is prolonged into a long narrow neck, as described by Castle for several species. The bunch of cells is, however, more compact than in the species described by him, each bunch being confined to a single segment—to the eleventh. The short Œsophagus leads into the crop, which is produced laterally into seven pairs of cæca in somites xiii to xix, the first and last of which are larger than the rest. The first, arising in somite xiii, passes forwards into somite xi; it is sacculated, overlies the ductus ejaculatorius, and is indented by its coils. The last similarly passes through about four segments, and is also sacculated. Each of the others is confined to its own segment.

A feature that I do not see noted in the description of other members of the family is a median gland surrounding the crop in somite xi; it consists of cells similar to the pharyngeal-gland cells, closely wrapped round the tube.

The stomach, occupying somites xxi to xxiv, is produced into four pairs of simple pouches, each enveloped as usual by a great dilatation of the dorsal blood-vessel. These gastric pouches are not strictly metameric: they are much crowded in the specimen, and lie-partly over one another. They appear to belong to somites xxi, xxii, xxiii, xxiv.

The intestine follows, and passes to the dorsally situated anus.

The nephridia were not traced out fully, nor was the total number enumerated; the funnels have a form typical for Glossosiphonids.

The Generative Organs (fig 5).—There are six pairs of testes (really testicular sacs), lying immediately behind the six anterior enteric cæca, and partially below them (probably due to curvature and the contracted condition of the individual); they lie in the annuli 31, 34 &c., to 46—i.e., in the posterior annulus of somites xiii to xviii. They are compressed by the neighbouring organs, but are more globular towards the margins of the body. They contain only a few sperm-morulÆ, as the spermatozoa had already been discharged into the seminal vesicles.

The six testes on each side are connected by short vasa efferentia with a dorsally situated vas deferens, which runs forwards into segment xiii and then bends backwards along the floor of the body in a very undulating course, to somite xvi; here each vas deferens opens into the seminal vesicle of its side.

The vasa efferentia open by ciliated funnels into the testes through the anterior wall, except in the last, where the funnel perforates the posterior wall.

The seminal vesicle may be regarded essentially as a cylindrical sac, but as it passes forwards it is much constricted and folded by the enteric cæca and by the vertical muscles, so that in reality its outline is very complex. It commences in somite xvi and passes forwards into somite xii, where it communicates with the narrow, muscular-walled ductus ejaculatorius. This is cylindrical, a good deal coiled in somite xi, and opens mesially into a pyriform or subspherical glandular sac, which may be termed “the spermatophoral sac”; it is transversely placed and opens with its fellow into a shallow, broad, common atrium, which in its turn communicates with the exterior between somites xi and xii.

Whitman (19) has described and figured the spermatophores of Placobdella parasitica (Clepsine plana), and discussed the question of the “hypodermic impregnation,” giving an account of the structure of the different regions of the sperm-duct, with which account the present species closely agrees.

The ductus ejaculatorius, when it issues first from the seminal vesicle, is lined by a low epithelium; further along this becomes a layer of high glandular cells, which reduce the lumen of the tube.

In the “pyriform sac,” in which Whitman believes the spermatophore is formed, the epithelium becomes still taller, and the lumen almost obliterated; the cells are much vacuolated in the specimen under consideration.

The seminal vesicle is distended with spermatozoa; the wall consists of a thin connective-tissue coat (staining blue in picronigrosin) lined with a low columnar, almost cubical, epithelium.

In segment xviii, on the left side of the body, situated just below the sixth enteric cæcum, is a mass of spermatozoa, not enclosed by any wall, but free in the body cavity: this mass is quite isolated from the seminal vesicle and from the testicular sac. It has, no doubt, arrived here by migration from the surface, as suggested by Whitman; and, in addition, I note a smaller mass dorsally above the gut.

The ovary (or ovarian sac) is a comparatively small lobulated sac, of short extent, occupying only two segments, xiii and xiv;

it has a thick wall, chiefly of connective tissue (staining blue in picronigrosin). In it is the usual coil of germ-cells, the true ovary or germarium. This “egg-cord” consists of very minute cells, only a few of which exhibit the characters of ova. I imagine, from this fact, and from the unusually short extent of the sac, that the ova have recently been discharged, and that when fully developed the sac would be longer.

The sac narrows to form a duct, which opens to the exterior in common with its fellow, at the hinder part of somite xii.

Hirudo mauiana, n. sp.

The opportunity of studying this, the second species of Gnathobdellid leeches to be recorded as occurring in New Zealand, I owe to Mr. H. Suter, who sent me nine specimens. They were obtained by Mr. Alfred Suter in water pumped up from a depth of 28 ft. in the grounds of the Farmers' Co-operative Freezing - works, at Penrose, Auckland. Probably, however, they are not truly subterranean, but live normally in some swampy region, or in ponds in the neighbourhood, and had been carried in some way into the well. The first individual to be obtained was thoughtfully sent to me alive, in October, 1905, and I was able to make a careful study of the coloration.

Colour.—The greater part of the dorsal surface is a dark olive-brown, paler and greener along the median line. This median band is bordered on each side by a linear streak of light yellowish-green. On each side the dark ground-colour is traversed by a well-defined band of light dusky-yellow, about midway between the median band and the margin of the body, which is reddish-orange. Except for the two admedian linear streaks and the marginal orange, there are thus seven nearly equal bands of colour—five dark and two yellow (fig. 6). The latter taper at each end, ceasing anteriorly at the level of the last pair of eyes, and posteriorly a few annuli in front of the sucker. The ventral surface is a uniform orange-red, which passes upwards round the margin on to the upper surface to form the marginal band just mentioned.

This individual was killed by adding alcohol gradually to the water, so that it retained its extended condition: it was then preserved in formol. When examined a year later the olive-brown had become a dark-grey, the admedian pale - greenish lines are now much paler—in fact, a dirty-white—and the conspicuous yellow bands are also dirty-white. The sucker is dark along the middle, but pale-yellowish along the right and left

sides. The remaining eight individuals preserved in alcohol exhibit the same pattern.^*

It will be evident, then, that the colour pattern is quite different from that of H. antipodum (2), though we do not know with certainty what are the true colours of this leech when alive. But as there are differences of greater importance in the internal anatomy, the distinctness of the two species is considerable.

Dimensions.—The living leech when fully extended—i.e., with both its suckers adhering to the table-top—measured 85 mm., and when contracted 25 mm., with a diameter of 7 mm. in the latter condition. The length when killed and preserved is now 70 mm.; the greatest breadth, which is a little behind the middle of the body, is 5 mm., but this is only slightly greater than the diameter elsewhere; and thickness 3 mm. The sucker, about 4.5 in diameter (fig. 7).

Of the remaining eight, the measurements are as follows (Nos. 2–5 were killed in alcohol, Nos. 6–9 in corrosive sublimate):—

The sucker is not quite circular, having the transverse diameter slightly greater than the longitudinal.

It will be seen that the specimens vary from rather less than 2 in. to nearly 3 in. in a preserved state, with a breadth of approximately ¼ in. No. 2 on the list is distended, probably with blood.

The leech is long and narrow, with a moderate sucker.

External Anatomy.—This was studied in specimen No. 1 when freshly killed.

There are the usual five pairs of eyes, on the annuli characteristic

(or seminal vesicle); when the duct leaves this it dilates to form a large ovoid muscular sac, from the anterior end of which a narrow duct passes transversely, to open into a median, globular, gland-covered “prostate,” from the posterior end of which the long, curved, muscular “penis-sac” (cirrus-sac) passes backwards, then bends forwards ventrally to open to the exterior at the male pore, just behind the sixth ganglion.

The most striking point in which this species differs from H. medicinalis is the presence of the ovoid muscular sac, which no doubt corresponds to the comparatively narrow muscular “ductus ejaculatorius” of that species.

The female organs consist of the usual pair of small ovarian sacs, each of which communicates by a narrow oviduct with the anterior end of a large gland-covered sac (the albumen-gland), from the hinder end of which a comparatively wide “uterus” passes backwards, then curves forwards ventrally and becomes the “vagina,” which opens by the female pore just behind the seventh ganglion. The “uterus” is readily distinguishable from the vagina by the different character of the wall, the latter having distinct circular muscles surrounding it.

In one specimen opened both the male and female duct lie on the right side of the nerve cord; in the second, the male is on the right and the female on the left side.

Remarks.—There is a superficial resemblance to a leech from New South Wales—H. australis, Besisto (3)—in which olive-brown and yellow bands alternate; but an examination of the coloured figures given by Becker (1) and by Schmarda (15) show essential differences in the arrangement of these bands.^* In it the yellow predominates over the darker tint, which, according to Schmarda and Besisto, is nearly black in life. The median dark band is quite narrow, bordered on either side by a slightly broader yellow band: this is followed successively on each side by two dark separated by two light bands of approximately equal breadth, much greater than that of the median and admedian bands; but the outer dark band is narrower than either of the yellow bands.

It is true that coloration alone may be insufficient to distinguish two leeches, for a considerable range of variation is known to occur in H. medicinalis—the best-studied species of Hirudo; nevertheless, Grube states that all the specimens studied by him exhibit the same pattern; and all my New Zealand

specimens agree with one another and in pattern, which differs from that of H. australis. It may be suggested that here we have two well-marked “local varieties” of one and the same species. Possibly this is the case; but if we turn to measurements we find that H. australis is a broader leech, and has a larger sucker.

The contrast with the present species is perhaps best rendered evident by a comparison of the two following diagrams:—

Explanation of Text Figures A and B.
Colour pattern of (A) Hirudo mauiana and (B) H. australis (copied from Schmarda). In both the various bands are lettered—in A, a is olive-green; b, greenish-yellow; c, e, olive-brown; d, bright-yellow; f, reddish-orange: in B, a, c, e are very dark olive (nearly black); b, c, yellow; f, brownish-orange.

Grube gives the measurements of two individuals (presumably preserved), and Schmarda gives the dimensions of another (apparently living). Taking a medium-sized individual (Grube's) and comparing it with a specimen from New Zealand of corresponding length, we have,—

Of internal structure we know nothing, excepting the jaws, of which Schmarda says that each jaw bears forty-eight to fifty denticles; and he shows them arranged along the entire margin, to increase in size towards one end, and to be of much greater size than in H. mauiana.

If Grube's synonymy be correct, I believe I am justified in creating a new species.

Hirudo antipodum, Benham.

My previous article (2) dealt only with such external features as seemed to be diagnostic of the species. I have now to give a brief account of the internal organs, as seen on dissection of a small specimen 25 mm. in length. The alimentary tract agrees in the main with H. medicinalis, though I was able to

detect only ten cæca, of which the anterior two are very small. The crop was partly filled with blood, the four posterior cæca being distended therewith; the three or four preceding cæca contained more or less blood, but there was none in the anterior cæca.

The pharynx appears to occupy a greater proportion of the body than usual; its hinder end reaches to a point at about one-third of the total length of the body, and covers both the median genital organs.^*

I have already, in my previous note, called attention to the edentulous condition of the jaws.

The genital organs (figs. 11, 12) differ considerably from the typical species—and, indeed, from any other species of Hirudo, so far as I can ascertain. There are only seven testicular sacs on each side; the vas deferens is relatively wide as it passes along the series, but anteriorly, in front of the testicular sacs, it becomes narrow, then presents the usual convoluted region, forming an epididymis or seminal vesicle, whence a narrow muscular “ductus ejaculatorius” passes transversely to a median gland-covered muscular sac of nearly spherical form, which opens directly to the exterior by its ventral surface. There is no narrow “cirrus-sac” such as occurs in other species of Hirudo. The filiform cirrus (which is protruded in one specimen) is contained within this globular sac, which may be termed “atrium.” It corresponds to prostate + penis-sac.

The female organs are also different from the type. The ovarian sacs are conspicuously large—larger, indeed, than the “albumen gland,” alongside which they lie. The muscular vagina is a short U-shaped tube, which, as it approaches the body-wall below the gland, becomes greatly dilated, so that its diameter is nearly as great as that of the overlying gland.

Remarks.—It may be necessary to form a new genus for this species, but at present I have not sufficient literature at my disposal to allow me to do so with surety.

The only other leech, so far as I am aware, in which the number of testes is so small as seven pairs is Philobdella, Verrill—which, however, is possessed of characteristic and unique “copulatory glands,” opening on to pits which appear to serve as adhesive organs in copulation. Moreover, the genital pores are separated by less than one somite; the annulations of the body in P. gracile, Moore (12), at any rate, being more complex than in Hirudo. There are also other differences. In Limnatis, however, the number of testes is eight pairs, according to Moquin-