The distinction of E. cookei from E. brucus is definite and striking, at least between sub-adult or adult specimens, but so far can be based only on the bucklerlike dermal denticles (Plate 7, Figs. A-D). There appear to be no significant differences in proportional dimensions,^* in external morphology, or in details of the teeth. However, the differences in the denticles lie not only in their relative size as mentioned above, though this alone is sufficient, but also in the shape and sculpture of the denticle bases (entire-margined or nearly so, and with rather fine radial ridging in E. brucus, but with strongly indented margins and coarse ridges (Text-fig. 2, E-H) in E. cookei), the presence in E. brucus of compound denticles up to 35 mm long, as a result of fusion of adjacent denticle bases, while such fused denticles are not a feature of E. cookei; and there is the tendency in E. brucus to retain noticeable-sized denticles on the underside of the snout and around the mouth even on large specimens, while in the type of E. cookei and in my specimen this area is virtually smooth, only a few minute denticles being present. For information on the last-mentioned feature in E. brucus I. am indebted to Dr. Denys E. Tucker, who examined five Mediterranean, Eastern North Atlantic and South African specimens, 910 mm to about 2,150 mm long, in the British Museum.

Comparison of my specimen with Pietschmann's (1930, p. 3) account of the type of E. cookei, a male 2,033 mm long and hence comparable to mine, shows close correspondence between them. Agreement in the dermal denticles is confirmed by enlargements from the negatives of the photographs used by Pietschmann in his Plate 1, A. and B; for these enlargements I. am indebted to Dr. Edwin H. Bryan, jun, Bernice P. Bishop Museum. With respect to the proportional dimensions of the type, it should be noted that Pietschmann gives the length of caudal as 5.2 in total length, while in my specimen the caudal is 3.8 if measured from subcaudal origin, and 4.2 if measured from upper caudal. Similarly other given dimensions involving the caudal indicate a shorter tail in the type than in my specimen, though this is not supported by reference to Pietschmann's photographs of the type. It would seem that Pietschmann either used a method of measurement different from that currently employed, or that he failed to make allowance for the undue upturning of the tail of his specimen as shown in his photograph. Some other of Pietschmann's dimensions also call for comment. His distance “from base of pectoral to tip of snout” as 5.2 in head is obviously in error, while “distance of nostrils” as 2.4 in head, and “depth of mouth (distance of middle of rear border from a line connecting both angles of mouth) 4.1 in breadth of mouth” do not match with his very good photograph of the underside of the head where the same dimensions appear to be about 5.0 and 2.8 respectively.

In my specimen these dimensions are 4.0 and 2.3 Unfortunately the type of E. cookei no longer exists, so that no check can be made on its dimensions, but from Pietschmann's account it can be said that other than in these apparently erroneous differences the type and my specimen agree closely in all respects.

The presence of E. cookei in regions as far separated as the tropical North Pacific (Hawaii) and the temperate South Pacific (New Zealand) suggests that it is a wide-ranging species likely to be encountered throughout the temperate and tropical Pacific as a whole, if not outside this ocean as well. This is supported by the recent capture of a 2,126 mm specimen off Peru (information kindly supplied in advance of publication by Miss N. Chirichigno), and also by the record of a Bramble Shark, 1,960 mm long, taken in 50–55 fathoms off California and reported by Hubbs & Clark (1945) as E. brucus, though it is in fact E. cookei. The photographs of

the Californian specimen in Hubbs & Clark's account indicate a lack of the large bucklers characteristic of E. brucus. This was confirmed through the kindness of Dr. Ernest A. Lachner, who examined the Californian specimen (deposited in the United States National Museum, Cat. No. 130667), and supplied a small representative sample of skin from high on the flank. The sample shows complete agreement in the dermal denticles with my specimen, the bucklers being mostly about 2 mm to 3 mm diam. and having strongly indented bases and prominent radial ridges. Dr. Lachner also reports that there are tiny scattered denticles on the underside of the head and snout, so that these regions are not entirely smooth (though more nearly so than in E. brucus) which is likewise in accord with my specimen. The dimensions of the Californian specimen as given in Hubbs and Clark's account parallel mine except for longer gill-openings, and the preocular length greater than the preoral—in my specimen the anterior margin of the eye is just in front of the level of the mouth. But I. do not regard these differences as warranting specific distinction.

The above-mentioned confusion of E. cookei with E. brucus poses the question of how many other reports of Bramble sharks as E. brucus (or its synonyms E. spinosus and E. mccoyi) are based on E. cookei. The diagnosis of E. brucus in many accounts is not sufficient to distinguish E. cookei. As an example, although Gunther (1870, p. 428) in his generic diagnosis of Echinorhinus gives “skin with scattered large round tubercles”, his diagnosis of E. spinosus is “each tubercle with a small spine in the centre”; the use of the word “small” in this context is likely to cause misinterpretation as to the size of the bucklers as a whole. The same can be said of Jordan & Evermann's (1896) account, where identical wording is employed. The question is unlikely to be answered for many, perhaps most records, unless they are fully descriptive of the denticles, or substantiated by illustrations, specimens, or fragments of specimens showing representative samples of denticles. Consequent on this, of the five New Zealand records of E. brucus, none can with certainty be confirmed as this species. These records are summarised below.

1884. Parker, T. J. (Trans. N. Z. Inst., 16: 280–281). Specimen caught off Dunedin, July, 1883, identified as E. spinosus from mutilated remains (jaws and tail). No description or illustration. (The jaws and tail cannot now be found in the Otago Museum where they were originally deposited.)

1886. Hamilton, A. (Trans. N. Z. Inst., 18: 135). Records, in footnote, specimen of E. spinosus taken at Napier, Hawke's Bay, in September, 1885.

1913. Waite, E. R. (Rec. Cant. Mus., II (1): 17) Identifies from photograph as E. brucus, a 2,567 mm specimen washed ashore at Opotiki, Bay of Plenty. No description or illustration.

1928. Phillipps, W. J. (N.Z. Journ. Sci. & Tech. X. (4): 221–222). 1,575 mm specimen recorded from Cook Strait as E. brucus Describes colour as rich brown with ovate black spots; denticles as circular bony tubercles with a sharp spine in centre.

1946. Phillipps, W. J. (Dom. Mus. Rec. in Zool., I. (2): 19–20). Reports jaws of specimen recently trawled off Hawke's Bay as E. mccoyi.

The black spots on Phillipps' (1928) specimen suggest E. brucus rather than E. cookei which is so far known only as uniformly coloured (some specimens of E. brucus are likewise reputed to lack such spots), while the description of the denticles as “circular bony tubercles” would also point to E. brucus. But these can scarcely be classed as definitive criteria, and in the absence of supporting specimens the presence of E. brucus in New Zealand waters seems to depend on the mounted skin (Pl. 7, C–D) in the Otago Museum which, as mentioned above, has not previously been recorded.

With regard to E. cookei, two occurrences^* in New Zealand other than the Palliser Bay specimen described here can be placed on record. The first of these is of a large specimen, reputedly about 4,000 mm (13 feet) long, taken in 35 fathoms off Shag Point, near Mocraki, towards the end of 1953, by Mr. R. Welsh. The photograph I. have of this specimen, which is the only evidence now available, shows clearly a uniform denticulation and absence of large bucklers. The reported length of this specimen appears to be a record for the genus—E. brucus is not known longer than about 3,000 mm—and from the photograph seems substantially correct in comparison with the size of the people surrounding the specimen. The second additional record is based on three juvenile specimens, 445 mm to 472 mm long, held in the collections of the Department of Zoology, Victoria University of Wellington. These juveniles in which the yolk-sac scars are just healed, were trawled in Cook Strait in either 1946 or 1947, and presented to the University by Mr. F. Abernethy. They show the same form of dermal denticles (Text-fig. 3, C) as the adult, but with two sizes of denticles present, of which the smaller are 0.5 mm to 0.8 mm diam and cover the whole body, including the underside of head and snout where they are almost as numerous as elsewhere. The larger denticles are 1.5 mm to 2.0 mm diam. (about half the size of adult E. cookei denticles) and are newly erupted or erupting; these are present mainly on the upper half of the trunk, above the lateral line; their distribution and spacing agree well with the adult. Despite these similarities the identification of the juveniles a E. cookei is made with some degree of caution, for the smallest denticles on the adult E. brucus in the Otago Museum have the same facies as those of my juveniles and hence also of adult E. cookei—i e, they have strongly indented, angular bases and coarse radial ridges (pers. comm. from Dr. R. R. Forster, Director, Otago Museum). Although the denticulation of juvenile E. brucus is not known, it can be inferred from Dr. Forster's observation that the small denticles on his adult are of juvenile from; hence such juvenile denticles will be common to both species, but will mostly be replaced by larger, circular-based denticles in sub-adult E. brucus. On these grounds the identification of my juveniles is necessarily tentative, except that the number, spacing and distribution of their larger denticles falls so closely into line with that of adult E. cookei, without suggesting the sparse and irregular distribution of E. brucus Further support for the belief that the juveniles are E. cookei is provided by Dr. Denys E. Tucker's examination of five specimens of E. brucus in the British Museum He reports (pers. comm). “as we proceed to larger specimens, it becomes evident that the definitive denticulation must be laid down at a relatively early age” His data give the size of large bucklers on a 910 mm male as up to 17 mm diam., while on a 1,690 mm male “the large denticles show no increase in absolute size and are rather more widely spaced”. This means that if my juveniles are E. brucus rather than E. cookei they would, in doubling their length (to reach the length of Tucker's smallest specimen) have to acquire a full array of adult denticles with diameters up to eight times that of their present 2.0 mm denticles. This seems unlikely.

The slenderness of the juveniles compared with the adult E. cookei is striking, especially along the posterior half of the trunk and the peduncle (Text-fig. 3A) where the depth of the body is relatively only two-thirds that of the adult. In other regions, including the head and the tail, the difference is less marked but still obvious. Relative longitudinal proportions are more nearly alike although the juveniles have rather longer heads and tails, as would be expected.

Differences between the juvenile and adult teeth are also remarkable, though apparently paralleled in E. brucus. The juvenile teeth, both upper and lower, are one-cusped (Text-fig. 3, D-E), the cusps strongly reflexed laterally so as to point almost horizontally. They are closely similar to those of Squalus in appearance but rather wider in relation to their height. The adult teeth are more erect, and have four or five cusps, there being one or two minor cusps on each side of the major cusp (Text-fig. 2, I-J). Behind the upper teeth, inside the mouth, is a prominent maxillary velum, fimbriated along its posterior margin, and with a narrow band of many fleshy papillae immediately internal to the teeth (Text-fig. 2, C). It resembles that of many batoids and is an unusual feature for sharks.

The lateral line of juveniles and adult is open for most of its length, as it is in E. brucus, forming a conspicuous white furrow from above the second gill-opening rearwards. In cross-section the upper edge of the furrow slightly overhangs the lower edge, especially in the adult. Each edge of the furrow is armed with a row of pointed spines, their tips directed rearwards; this also agrees with the condition described for E. brucus in Bigelow & Schroeder (1957, p. 134) Closer examination shows that the spines are not discrete units but are the free ends of regularly placed, incomplete skeletal rings, lying inside transversely across the furrow and supporting its walls (Text-fig. 1, A-C); presumably these rings, which have not previously been described, are derived from dermal denticles. They are unique not only for the Squaloidea but for all other true sharks as well (excluding here the Chimaerae

Text-fig. 1.—Fig. A, semidiagrammatic view of lateral line from trunk of 445 mm juvenile Echinorhinus cookei (Dom. Mus. No. 2792) showing ring-like skeletal elements (SR) with pointed tips bordering the edges of the open furrow Fig. B, skeletal elements of lateral line from same specimen and position as Fig. A, but drawn from dried skin Fig. C, semidiagrammatic view of lateral line from trunk of 1,980 mm Echinorhinus cookei (neotype, Dom. Mus. No. 2774) New Zealand, showing similar features as Fig. A, though skeletal rings (SR) may have bifid tips, the furrow is more nearly closed and is bridged at intervals by skin (BR).