C. nilsoni has been known only from the holotype, a male 1,030 mm long, taken in deep water off Kaikoura, New Zealand, in 1928, and a second specimen recently recorded from south-eastern Australia by Cowper and Downie (1957, p. 9, and Appendix p. 7). C. foliaceus is known from at least four specimens, 325 mm to 407 mm long, from japan and the Philippines, in depths of 345 fathoms to 960 fathoms, while Richardson's (1956, p. 7) illustration of a specimen^* from Kaikoura extended its known range to New Zealand.

The present study of these two species is based on the holotype of C. nilsoni (preserved in the Canterbury Museum, but in a very desiccated condition); a second New Zealand specimen referable toC. nilsoni, a female 1,370 mm long from 500 fathoms off Kaikoura; and eight specimens seemingly C. foliaceus, 438 mm to 515 mm long, also taken off Kaikoura in 200 fathoms. The capture of all these specimens other than the holotype is due to Mr. Richard Baxter of Kaikoura, whose co-operation in carrying out experimental line-fishing in deep water during 1954 and 1955 is greatly appreciated.

Comparison of the second New Zealand specimen of C. nilsoni with the holotype shows no significant differences. Their proportional dimensions, expressed as percentages of total length, agree very closely, as shown in Table I, columns E and F. The extended posterior corner of the pectoral fin is longer in the second specimen, being 1/9th of the length of the fin compared with 1/12th in the holotype. The dorsal fin spines of both specimens are comparatively short, but close examination shows that they have a worn or eroded appearance. If this is the case, it may be the explanation for the fact that the 2nd spine is shorter than the 1st in the holotype, whilst the reverse holds true for the second specimen and is the usual condition for other species in the genus. Both the upper and the lower teeth of the holotype are slightly more erect than those of the second specimen; and while there is a symmetrical, median lower tooth in the holotype, its equivalent is oblique in the second specimen. Similar variation in this latter feature is recorded for C. squamosus and C. uyato (Bigelow and Schroeder, 1957, p. 72). The cusps of the lower teeth in both specimens have irregularly and finely serrate cutting edges (Text-fig. 2, H, as C. squamosus), which is also a feature of other species in the genus. But the same condition occurs in the cusps of the upper teeth (Text-fig. 2, G, as C. squamosus), some of which in both the functional and the reserve series of both specimens show traces of irregular serration of their cutting edges, particularly at the shoulders of the cusps. This feature is not as prominent, nor as general in the upper teeth as it is in the lower, and because of the smaller size of the upper teeth, is readily overlooked. It is not known for other species of the genus except for C. granulosus as figured in Bocage and Capello (1866, Pl. 1, Fig. 3, E), though Bigelow and Schroeder (1957, p. 67) report that the upper teeth in two specimens of C. granulosus that they have examined are smooth. The dermal denticles of both specimens are scale-like (Text-fig. 3, as C. squamosus), subovoid in shape, each with three longitudinal ridges, and terminating in a sharply pointed median tooth which is flanked on either side by one to several small, irregular lateral teeth; the number of these lateral teeth is greater in the second specimen than in the holotype, but in all other features the denticles are the same.

The New Zealand specimens referable to C. foliaceus agree closely with the description and illustrations of the holotype of this species. The range of proportional dimensions expressed as percentages of the total length of five of these specimens is shown in Table I, column C, for comparison with those of the holotype, column B, and a smaller specimen from Japan, column A. Furthermore, Mr. N. B. Marshall of the British Museum, who has compared one of the New

Zealand specimens, a female 462 mm long, with the holotype, and who has checked on the details of the teeth, denticles, fins, fin-spines and preoral clefts, reports that he can find no differences between them (personal communication). The condition of the posterior corner of the pectoral fin, which in the holotype is so little extended that it is best described as quadrate, is matched in some of the New Zealand specimens; but in others the extension is well marked so that its length approximates to 1/20th the length of the fin (Text-fig. 1, A). One feature of some of the New Zealand specimens, which does not occur in the 351 mm male from Japan described by Bigelow and Schroeder (1957, p. 78) and apparently not in the holotype either, is the presence of irregular and fine serrations on the cutting edges of the lower teeth (Text-fig. 4, J, as C. squamosus). The extent to which these are present, in both the functional and reserve rows, is about the same as in the specimens of C. nilsoni, but they are most prominent only in the teeth of the larger specimens of C. foliaceus. The upper teeth are generally smooth, but as they are so small, such irregularities as are present on their cutting edges could as equally be described as serrations as could the irregularities which are evident in the “smooth-edged” cusps of the upper teeth of other squaloid sharks when sufficiently magnified.

All the known male specimens of C. foliaceus are immature, as evidenced by their claspers, which are only half to two-thirds as long as the posterior inner margin of the pelvic fin in the 351 mm specimen from Japan (Bigelow and Schroeder, 1957, Fig. 7, F), the 480 mm specimen from New Zealand (Text-fig. 4, A, as C. squamosus), and the holotype of 407 mm (personal communication from Mr. A. C. Wheeler of the British Museum). The female specimens from New Zealand show little or no development of the ovaries, oviducts, or uteri. Perhaps a better indication of the immaturity, and in fact juvenile status, of the known specimens of this species, is the presence of obvious, recently-healed yolk-sac scars on all the New Zealand specimens. Such scars are also evident on two Japanese specimens of 351 mm^* but not on the holotype. However, it is reasonable to assume from the size of the latter compared to the New Zealand and Japanese examples, and the state of its claspers, that it is also a juvenile.

The presence in New Zealand waters of two “species” of Centrophorus, resembling each other closely in most features, and falling into two very distinct age-groups, one represented by the mature specimens of C. nilsoni more than 1,000 mm long, the other by the immature and juvenile specimens of C. foliaceus 400—500 mm long, with no other size-groups of either “species” known, suggests, a priori, a parent-juvenile relationship. The basis for assuming this relationship is provided, firstly by the size of the recently-born C. foliaceus—a size which demands that they grow into adults maturing at 1,000 mm or more, and hence adults the size of C. nilsoni. Secondly, comparison of the proportional dimensions of C. foliaceus (Table I, columns A, B and C) with those of C. nilsoni (columns E and F) shows striking agreement between them. Of the differences in dimensions that do occur, particularly between the smallest specimens of C. foliaceus and the two specimens of C. nilsoni, many can be disregarded when the range of variation shown for the same feature by the five New Zealand specimens of C. foliaceus is taken into account. Thus the length of base of the 1st dorsal fin is 6.6% in the holotype of C. foliaceus and 9.8% in the holotype of C. nilsoni, a difference that would appear significant. But in the five New Zealand specimens of C. foliaceus, all somewhat larger than the holotype, the range for this feature is 7.3% to 8.2%, thus bridging the gap. The same holds true for the apparent discrepancies in the distance from the snout to the gill-openings, and for other proportions too. However, not all the differences

Text-fig. 1.—Figs. A–D, pectoral fin outlines of some species of Centrophorus. Fig. A—C. foliaceus, male 497 mm, New Zealand; Fig. B—C. acus, holotype, male 819 mm, Japan (after Bigelow and Schroeder, 1957, Fig. 8, D); Fig. C—C. squamosus, female 1,230 mm, Iceland (after Bigelow and Schroeder, 1957, Fig. 8, B); Fig. D—C. nilsoni, female 1,370 mm, New Zealand.

Figs. E–G—Dermal denticles from some species of Centrophorus. Fig. E—C. foliaceus, male 480 mm, New Zealand. Fig. F—C. acus, holotype, male 819 mm, Japan (after Garman, 1913, Pl. 12, Fig. 8). Fig. G—C. nilsoni, female 1,370 mm, New Zealand.

Fig. H—A group of dermal denticles from high on the side of a female specimen of C. foliaceus, 515 mm, from New Zealand, showing four larger and wider newly-erupted denticles, and four smaller and older denticles.

can be explained in this way, as for example in the case of the distance from origin to origin of the pectoral and pelvic, these being 36.2% and 44.8% of the total lengths of the holotypes of C. foliaceus and C. nilsoni respectively. Allowing for the variation in this feature of the New Zealand specimens of C. foliaceus (33.0% to 37.4%) and the two specimens of C. nilsoni (41.1% to 44.8%), a difference of about 4% still remains. It seems not unreasonable to attribute this, at least in part, to variation with growth of the species, about which little is known for elasmo-branchs in general other than that it does occur.

If the above assumptions on the meaning of the differences between the dimensions of C. foliaceus and C. nilsoni are correct, any basis for separating these species must depend on morphological detail. In this respect, various characters have been put forward. Fowler (1941, p. 229) separates C. nilsoni from C. foliaceus

because in the holotype of the former the 1st dorsal fin is slightly higher than the 2nd. But in the second specimen of C. nilsoni the reverse is true, and hence in agreement with the usual condition in C. foliaceus Bigelow and Schroeder (1957, p. 83) distinguish C. nilsoni from C. foliaceus because firstly the posterior pectoral corners are extended in C. nilsoni but quadrate in C. foliaceus; and secondly because the fin spines of C. nilsoni are low and largely covered, whereas those of C. foliaceus are long and well-exposed. The New Zealand specimens of C. foliaceus show much greater variation in the length of the pectoral extension than was formerly known for this species, so that although the specimen of C. foliaceus on which Bigelow and Schioeder based their key characters had quadrate posterior pectoral angles as do also some of the New Zealand specimens, others have pectoral extensions of 1/20th the length of the fin. The difference between C. nilsoni and C. foliaceus is, then, at the least, the difference between extensions 1/12th and 1/20th the lengths of the fins respectively (Text-fig. 1, A and D), a difference which can hardly be sustained as a key character when allowance is made for possible variation with growth.

The fin spines of C. nilsoni emerge from the anterior margins of the dorsal fins at about the same height from the bases of the fins as do those of C. foliaceus. Their bases are, then, covered to the same extent with integument as those of C. foliaceus. As stated above, the spines of C. nilsoni appear worn or eroded; if this is the case, then the reduction in their extremities would give them the appearance of being “low and largely covered”, as described by Thompson (1930, p. 277) and used as a key character by Bigelow and Schroeder.

The only other character by which C. foliaceus can be separated from C. nilsoni is the nature of the dermal denticles. Those of C. foliaceus are long, blade-like and tridentate, with a high median ridge, and rise steeply from the skin (Text-fig, 1, E; Text-fig. 5, A—E, as C. squamosus); while those of C. nilsoni have subovoid blades, with a shorter medium tooth, several inconspicuous lateral teeth, and lie along the skin rather than away from it (Text-fig. 1, G; Text-fig. 3, A—D, K, as C. squamosus). The difference between these two types of denticles are considerable, but in view of what is now known of denticle changes with growth in species of other squaloid genera, particularly in the genus Centroscymnus (described in detail for C. coelolepis in Bigelow and Schroeder, 1954, p. 47), they cannot be accepted without question as criteria for specific distinction. Certainly the denticles of C. foliaceus resemble those of the juveniles ofCentroscymnus spp. in which denticle changes do occur— in other words such juvenile denticles share common characteristics of being markedly tridentate, with a very long median tooth half or more of the total length of the blade; with considerably shorter lateral teeth, and with the blades rising steeply from the skin as is the case in the juvenile of Centroscymnus waitei (see Garrick, 1955, Text-fig. 2D). Direct evidence is available, however, that denticle changes do, in fact, occur in C. foliaceus. Examination of the largest of the New Zealand specimens of C. foliaceus, a female 515 mm long, shows that although the majority of the denticles on the flank below the first dorsal are like those of the smaller specimens and of the holotype, there are, scattered throughout them, newly erupted denticles, not yet pigmented, rising less steeply from the skin, and of a different shape (Text-fig. 1, H). These new denticles are larger, wider in proportion to their length, and have a shorter median tooth. Most of them are tridentate, but some have two or three iiregular lateral teeth on each side, and thus show some approach to the type of denticle found in C. nilsoni. In Centroscymnus coelolepis, the final generation of denticles appears on specimens slightly more than half-grown; if the same applies to C. foliaceus, it could be expected that only on specimens 700—800 mm long or longer would adult type denticles be found. As the largest known specimen of C. foliaceus is only 515 mm, it cannot be expected to show adult type denticles. From a slightly different viewpoint, the absence of adult specimens

with “foliaceus” type denticles, though at least 12 juvenile specimens are known from a wide range of depths, in itself appears significant, and suggests that adult “foliaceus” type denticles are non-existent, presumably through their replacement by denticles of another type.

On the basis of this evidence, the separation of C. nilsoni from C. foliaceus is not justified. Accordingly they are regaided here as one species for which the name C. foliaceus would have priority.

Comparison of C. foliaceus as recognised above, with other species of Centrophorus shows that further integration is possible. The genus Centrophorus includes three species groups, well characterised by the nature of their denticles, which may be block-like, scale-like or conical. The group with scale-like denticles, to which C. foliaceus belongs, includes, as recognised currently by Bigelow and Schroeder (1957) in their masterly review of the Squaloidea, only two other species These are C. squamosus (Bonnaterre) 1788, from the eastern North Atlantic, and C. acus Garman, 1906, from Japan. Both of these species closely resemble C. foliaceus in their overall morphology. In fact, their proportional dimensions, as shown in Table I, columns G and D, give no reason for their separation.

The apparent distinction of C. squamosus from C. foliaceus because its first dorsal base measured from the origin of the spine is about twice as long as that of the second when similarly measured (as illustrated in Jensen (1899, Pl. III, A) and used as a key character by Bigelow, Schroeder and Springer (1953, p. 225)) cannot be sustained, for in a 1,250 mm specimen of C. squamosus (Mus. Comp. Zool. No. 37825) from Iceland the lengths of the dorsal bases are 9 8% and 7 8% of the total length respectively, and thus well in accord with those of C. foliaceus (personal communication from W. C. Schroeder).

The posterior corner of the pectoral fin of C. squamosus (Text-fig. 1, C) has about the same degree of extension as that of adults of C. foliaceus (Text-fig. 1, D, as C. nilsoni) And the excellent illustrations of the teeth and denticles of C. squamosus in Jensen (1899, Pl. III, B—R) agree so closely in their details with those of the New Zealand adults of C. foliaceus (Text-fig. 2, E—H, Text-fig. 3., A—K, as C squamosus) that there can be no question of distinction in these features.

There is, then, no reason for separating C. foliaceus from C. squamosus, the latter name having priority This makes C squamosus a bipolar species, and parallels the case of Centroscymnus crepidater Bocage and Capello, 1864, previously known only from the North Atlantic, but recently recorded from New Zealand (Bigelow and Schroeder, 1957, p 93).

The relationship between C. squamosus as recognised above and C. acus is not as clear cut. Their proportional dimensions agree closely (Table I), as do the lengths of their pectoral fin extensions, or the details of their teeth. However, the denticles of the holotype of C. acus, as illustrated in Garman (1913, Pl. 12, Fig. 8) and Bigelow and Schroeder (1957, Fig. 11D) differ markedly from those of either juveniles or adults of C. squamosus, but they have a close resemblance at least in outline to the few newly-erupted denticles in the New Zealand specimen of 515 mm now regarded as C. squamosus (cf. Text-fig. 1, F, with 1, H). If C. acus does represent a growth stage of C squamosus, then the denticles on a specimen the size of the holotype (819 mm long) would, on the assumptions made above, approximate to those of adults of C. squamosus, that they resemble, in outline, the denticles of more juvenile specimens may mean that C squamosus undergoes denticle changes at a later stage than specimens of Centroscymnus coclolepis. Alternatively, it may indicate that C. acus is a distinct species.

Bigelow and Schroeder (1957, p. 78) further separate C. acus from C. foliaceus on the grounds that the denticles of C. acus are less regularly overlapping, and relatively smaller. Little reliance can now be placed on the first of these characters because of its varrability with growth The denticles of the holotype of C. foliaceus

Text-fig. 3.—Centrophorus squamosus, male 1,030 mm (holotype of C. nilsoni), New Zealand Figs. A–G—Dermal denticles from high on side at level of 1st dorsal fin Fig. A—external view showing arrangement of denticles. Fig. B—External view of denticle showing underlying base Fig. C—Lateral view. Fig. D—Apical view. Figs. E—G—Outlines of denticle bases, showing variation in the scalloping of the anterior margins, and the major and minor ridges. Fig. H—Denticle from caudal fin. Fig. I—Denticle from 0.5 cm posterior to lower lip. Fig. J—Denticle from margin of lower lip. Fig. K—C. squamosus, female 1,370 mm, New Zealand: dermal denticle from high on side at level of 1st dorsal.

(407 mm long) are more overlapping than those of any of the New Zealand specimens. including the smallest (438 mm), originally ascribed to this species. Presumably the greater spacing of the denticles on these slightly larger specimens is due to growth of the trunk separating the individual denticles of the first generation. Succeeding generations of denticles, the first of which are appearing in the 515 mm specimen, would close the gaps so produced.

Whether the smaller relative size of the denticles of C. acus is significant must remain unanswered until further specimens of this species are available; other evidence suggests that it may, in fact, reflect specific distinction. Although the denticles of C. acus have the same shape as the newly-erupted denticles in the 515 mm specimen of C. squamosus from New Zealand, they differ in other features. The median longitudinal ridge on the blade of each denticle of C. acus is “relatively feeble” (personal communication from W. C. Schroeder who has compared the denticles of the second adult specimen of C. squamosus from New Zealand with those of C. acus); this contrasts strongly with C. squamosus, where the median ridge is very high, not only in adult denticles, but also in those of juveniles. And as well, the pedicles of the denticles of C. acus are wider, in lateral view, than are those of C squamosus Other differences between C. acus and C. squamosus are the shape of the pectoral fins, the distal margins of which slope posteroventrally in C. acus when the fin is adpressed to the trunk, whereas those of C. squamosus are almost vertical (cf. Text-fig. 1, B, with A, C and D); and the less tapered snout contour of C. acus, as shown in the illustrations of the holotype (Garman, 1913, Pl. 12, Fig. 7).

C. acus is therefore considered as distinct, though further specimens may show

Head measured to 1st gill-opening about 5.9—6.2 in the total length. Head depressed and strongly wedge-shaped in profile so that the snout tip is markedly pointed. The least fleshy interorbital distance is at the anterior level of the eyes where it is 2.2 in the head. Snout short, greatly depressed and thin, and with a definite ventrolateral edge which is prominent from the level of the mouth to the tip of the snout. Contour of snout from above bluntly pointed at the snout tip, with almost straight margins extending posteriorly to the level of the nostrils, where the margins are slightly convex. Posterior to the nostrils the head contours gradually widen to reach the maximum width of the head at the level of the 1st gill-opening. Length of snout measured to the eye 3.4–4.0 in the head and just less than or equal to the horizontal diameter of the eye Eye large, oval, almost three times as long as high, its horizontal diameter 3.3–3.4 in the head. Spiracle large, and placed level with the dorsal margin of the eye and posterior to it by a distance equal to its own height. Gill openings vertical, concave and in a horizontal series anterior to the pectoral base. Lengths of the gill-openings increasing from the 1st to the 5th, the latter being 1.5.—1.7 in the horizontal diameter of the eye. The interspaces between the 1st and 2nd, 2nd and 3rd, and 3rd and 4th gill-openings subequal, and about 1.5 times that between the 4th and 5th. Nostrils of moderate size, slightly oblique, and placed well anterior on the ventral surface of the snout Interspace between the nostrils 1.5—1.8 in the snout. Each nostril subdivided into two apertures, one lateral and subcircular, the other medial and subovoid, by the anterior and posterior nasal flaps which are extensions of the anterior and posterior nasal margins. The anterior flap is triangular, thin, sharply pointed and directed posteriorly, and external to the deeper and rather fleshy posterior flap. The medial nasal aperture is margined, anteriorly and posteriorly, by a naked membranous fold Mouth moderately arched and broad, its width just less than the preoral distance. Preoral clefts rather short, reaching one-third of the distance from the corners of the mouth to the upper symphysis, but extended posteriorly as furrows which are twice as long as the preoral portion.

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Teeth 16–1–15/14–1–9 in the male, 17–1–17/14–15 in the female, dissimilar in the two jaws. The upper teeth erect, at least at the centre third of the jaw, though towards the angles the cusps become stiongly oblique, more so in the female than in the male. Each upper tooth with a moderately short, sharply-pointed, mainly smooth-edged, awl-shaped cusp borne on a square to rectangular base. The basal portion of each cusp is expanded on both the medial and lateral sides, where it joins the base, but its continuation on to the base is abruptly constricted so that the cusp as a whole stands out from the base as a short, dagger-shaped structure with an enamelled blade. Some of the upper teeth, in both the functional and reserve series, show traces of irregular serration of their cutting edges, particularly at the shoulders of the cusps, though it is not a prominent feature. The teeth in the middle third of each side of the upper jaw are slightly larger than those towards the symphysis or the angle. Three to four series of teeth functional at the centre of the jaw, two or three towards the angles. The lower teeth blade-like, each with a quadrangular base with rounded angles and bearing a single, sharply-pointed, triangular cusp Each cusp, with the exception of that of the symmetrical median tooth in the male (no equivalent tooth is present in the female) is oblique and deeply notched laterally where it joins the base. In the male, the cusps are much less oblique, particularly at the centre of the jaw, than those in the female, where the cusps are so reflexed as to form an almost continuous cutting edge. The cutting edges on the median side of all the cusps are slightly sinuous and irregularly and finely serrate, while those on the lateral side are almost straight and mostly smooth-edged. Two series of lower teeth are functional.

First dorsal large, of moderate height but with a long base, and originating smoothly from the dorsal profile a little anterior to the level reached by the posterior tip of the pectoral when the latter is adpressed to the side of the trunk. Height of the 1st dorsal 2.0–2.3 in the length of that part of its base measured from the origin of the 1st dorsal spine to the posterior insertion of the base. The 1st dorsal spine short, the length of its exposed tip a little more than one-third of the height of the 1st dorsal, and its origin about halfway along the anterior margin of the fin. The apex of the 1st dorsal rounded, the distal margin weakly concave or straight. The 2nd dorsal similar to the 1st, but with a shorter base. Origin of the 2nd dorsal just anterior to the level of the insertion of the pelvic fin. Length of the posterior part of the 2nd dorsal base measured from the origin of the 2nd dorsal spine to the insertion of the base, about 1. 5 in the length of the equivalent portion of the 1st dorsal base. The 2nd dorsal spine very short in the male, the length of its exposed tip 3.0 in the length of the 1st dorsal spine, in the female the 2nd dorsal spine is slightly longer than the 1st. The anterior margin of the 2nd dorsal fin convex, the apex smoothly rounded and distal margin slightly concave. The posterior free tip pointed and extending well posterior to the hypural origin but just failing to reach the epiural origin. Caudal measured from the hypural origin 5. 2 to 6. 2 in the total length, the cpiural lobe moderately developed, the hypural lobe deep Height of the epiural lobe about 3. 5 in its length and 1. 5 to 2.0 in the height of the hypural. The margin of the epiural almost straight, the terminal lobe truncate or slightly concave and separated from the hypural lobe by a distinct subterminal notch. Origin of the hypural well anterior to the origin of the epiural

Text-fig. 5.—Centrophorus squamosus, male 480 mm, New Zealand Figs. A—E—Dermal denticles from high on side at level of 1st dorsal fin. Fig. A—External view of three denticles, showing wide spacing. Figs. B—C—External views. at different angles, of a denticle, showing its underlying base. Fig. D—apical view. Fig. E—Lateral view. Fig. F—Denticle from inter-orbital region. Fig. G—Denticle from upper lip. Fig. H—Denticle from lower lip. Fig. I—Denticle from caudal fin. (N. B.—Figs. A—B are at right angles to the surface of the skin. Figs. C, F—I are at right angles to the surface of the blade of the denticles.)

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and midway between the insertion of the 2nd dorsal base and the posterior free tip of the 2nd dorsal fin. The lower anterior margin of the hypural concave at its origin but convex towards the apex, the margins of which form an acute angle though the apex itself is rounded. The posterior hypural margin concave. The pectorals about twice as long as broad, and originating just posterior to the 5th gill-openings. Length of the pectorals 1. 3 to 1. 5 in the head, so that when adpressed to the sides of the trunk they fail to reach the origin of the 1st dorsal spine by a distance equal to 2/3 or more of the horizontal diameter of the eye. The anterior margin of the pectoral straight for the proximal 2/3 of its length, but slightly convex distally. The posterior angle extended as a pointed tip about 1/9th to 1/12th the length of the anterior margin. In the male this extension was described by Thompson as being on the right fin only, and “practically absent” on the left, though whether this might be due to damage or wear was not stated. The distal margins of both pectorals of the male have since been damaged so that no further comment is possible In the female, the left pectoral fin extension is present, but not the right, though it is obvious from examination that the posterior angle of the right fin has been damaged or worn.

The pelvics originate well posterior to the posterior tip of the 1st dorsal, the interspace between these levels equal to or greater than the length of the posterior part of the 1st dorsal base measured from the origin of the 1st dorsal spine to the insertion of the base. The anterior, distal and posterior pelvic margins straight, the apex sharply rounded, and the posterior free tip pointed and terminating a little posterior to the level of the 2nd dorsal spine. The claspers

ovoid in section and sharply pointed distally, their tips slightly upturned and extending behind the posterior free tip of the pelvic fin for a distance equal to half the horizontal diameter of the eye. A subterminal lateral spur is present on each clasper, but is so closely adpressed to the side of the clasper that it is not obvious on superficial examination.

Colour (in formalin): Uniform greyish brown.

(b) juveniles: Text-fig. 4, A—J;, Text-fig. 5, A—I; Text-fig. 1, H (as C. foliaceus.)

For proportional dimensions in per cent. of total length, see Table I, column C (as C. foliaceus.

Description as for adults, except as given below; based on male 480 mm and female 515 mm T.L.

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Height of trunk at origin of pectorals about 1/8 of its length to origin of caudal. Length of body measured to cloaca, 61% of the total length.

Dermal denticles of moderate size, bristle-like to the touch, distributed uniformly but loosely so that there are considerable interspaces between the blades, and clothing the entire body except the axils of the fins and the lower lip. The dermal denticles of the trunk each with an erect, slender, tridentate blade borne on a four-angled pedicle arising from an essentially thomboidal-shaped base. The blades are directed posteriorly away from the surface of the skin so that the angle between the under surface of each blade and the skin is about 50° or more. Each blade is produced distally as a long and sharply pointed median tooth flanked on each side by a short, sharp, lateral tooth which reaches only about half-way along the length of the blade. The external surface of each blade carries a high, steep-sided median ridge, which is sharp-topped distally where it extends to the tip of the median tooth, but round-topped towards the basal end of the blade where it also has a shallow, longitudinal groove along its crest. This median ridge extends without interruption from the blade on to the pedicle and is continuous with the ridge arising from the anterior angle of the base. In the female of 515 mm, there are in addition to the denticles just described, newly-erupted denticles of a different shape, scattered throughout the others on the sides of the trunk. These new denticles are not yet pigmented, and rise less steeply from the skin. They are slightly longer, but 1½ times to twice as wide, so that the median tooth is relatively shorter. Mostly the blades are tridentate, with a high median ridge, but a few have two or three irregular lateral teeth on each side of the median tooth. The base of each denticle has four major angles, from which the four major ridges arise, but in addition there is one and sometimes two minor angles on the anterior margin of each side of the base, so that each of these anterior margins is shallowly scalloped either two or three times. From each of the minor angles there is a minor ridge extending on to the pedicle. The denticles from the inter-orbital region have the same facies as those from the trunk, except that the blades are much shorter and wider, and in many instances there are two lateral teeth on each side of the median tooth. The denticles from the snout and upper lip have subcircular blades, each of which terminates in a median tooth, and there are no lateral teeth. The median ridge is also considerably lower and usually just fails to reach the tip of the median tooth, while the lateral margins of each blade are thickened so that there is an incipient ridge on each side. The denticles from the lower lip are almost sessile, each having a heavy, subcircular blade terminating in a blunt median tooth, and bearing two lateral ridges on each side in addition to the low, median ridge which is itself subdivided into two ridges by the prominent longitudinal groove on its crest. The denticles from the tail are similar to those from the trunk region, though the basal end of each blade is elongated, so that the lateral teeth reach about three-quarters of the way along the blade instead of only half-way. The base of each caudal denticle has only the four primary angles and ridges, there being no scalloping on the anterior margins.

Head measured to 1st gill-opening 5. 1 to 5. 3 in the total length. The least fleshy inter-orbital distance 2. 4 in the head. Length of snout measured to eye 3. 2 in the head. Horizontal diameter of eye 2. 8 in the head. Lengths of the gill-openings increasing slightly from the 1st to the 5th, the latter 2. 4 in the horizontal diameter of the eye. Interspace between the nostril 1. 8 to 2.0 in the snout.

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Teeth 16–17/14–15 in the female of 515 mm. Some specimens with a symmetrical median upper tooth, but none with a symmetrical median lower tooth. The degree of obliquity of the cusps of both the upper and lower teeth varies somewhat, but in all specimens it increases considerably towards the angles of the jaws. Lower teeth on the larger specimens with irregular serrations on their cutting edges.

Height of the 1st dorsal fin 1. 6 in the length of that part of its base measured from the origin of the 1st dorsal spine to the posterior insertion of the base. Tip of the 1st dorsal spine just failing to reach the apex of the fin. The 2nd dorsal fin just higher than the 1st, but with a shorter base. The 2nd dorsal spine similar to the 1st, but slightly longer. Caudal measured from the hypural origin 4. 2 to 4. 3 in the total length. Height of the epiural lobe