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Show 1868.] ON A SUPPOSED NEW GALEOCERDO. 369 by Muller and Henle (pl. 24), and by Prof. Owen (in his 'Odontography,' pl. 28. fig. 9) of the northern Tope bear a general resemblance to those of M r . Rayner's specimens, yet, on careful comparison, the latter are found to be more delicately crenulated towards their summits. In colour the southern Tope (G. tiejri-nus), figured by Muller and Henle in plate 23 of their work, has something in common with our Shark, particularly in the form and disposition of the markings ; but in the general contour, and in the proportion of the fins, there is much disagreement. This is especially noticeable in the tail; for whereas in G. tigrinus the caudal fin, measured from the tail-pits to its extremity, is more than a third of the entire length of the fish, in M r . Rayner's Shark this member is only a little more than a fourth of the extreme length, and agrees better with the tail of G. arcticus as well in proportion as in form. The two Australian jaws collected by M r . Rayner have been carefully compared with six entire jaws and a portion of a seventh, collected in southern seas by different naval officers, w h o presented them, at various times, to the Haslar Museum*; and they have been found to agree in every particular. With such evidence of the apparent frequency of this Shark, and of its range in southern seas, one might be led to consider it identical with the known southern Tope ; but there are also distinctive characters which we think sufficient to afford good presumptive evidence of the existence of a marked variety, if not a distinct species ; and in honour of the gentleman whose labours have furnished much material and many interesting facts relating to this group of fishes, we wish to bestow on it the provisional name of Galeocerdo rayneri. Mr. Rayner's notes, taken from the recent specimen, are here transcribed:- " Dimensions of a female fish taken in March 1858. feet. in. " Length to tail-pit 6 2 Length of tail-fin 2 3| Girth...., 3 8£ " Head short, flat and inflated at the angles of the jaws; snout short and rounded ; nostril slit transversely, with a conical flap attached to the inner side of the anterior border, and the external * 1. Large entire jaw from St. Thomas, Virgin Island, presented by Francis Cole, Esq., E.N. 2. Large entire jaw, locality unknown. 3. Large entire jaw, from the west coast of Australia. 4. Large entire jaw, from near Lord Howe's Island, presented by F. M. Eayner, Esq., E.N. 5. Large entire jaw, locality unknown. 6. Entire jaw of smaller size, locality unknown. 7 Portion of jaw of large size, from the Pacific, presented by - Wood, Esq., E.N. PROC. ZOOL. Soc-1868, No. XXIV. |