722 PLAGIOSTOMATA— SELACHOIDEI. 



Family, II— LAMNID^E. 



Spiracles, if present, minute. No membrana nictitans. Mouth inferior and crescentio. Nostrils not 

 communicating with the mouth. First dorsal spineless, and placed opposite the interspace between the 

 pectoral and ventral fins : an anah fin present. 



I tave (p. 713) described a shark, Garcharias tricuspidatus, the teeth of which so closely resemble those 

 seen, in Odontaspis, that specimens have been erroneously referred not only to that Genns but to the 

 0. Americanus. The absence or presence of the pit at the root of the caudal fin is one character which at once 

 distinguishes the two forms, for if they were identical species the character of the pit at the base of the caudal 

 fin as a distinguishing guide would have to be given up, not only as a generic but even as a specific character. 



Genus 1 — Lamna, Owvi&r. 



Oxyrhma, Agassiz. 



Spiracles, if present, rtmrnte. No memhrana nictitans. Mouth wide. Gill-openings large. Teeth la/rge, 

 awl-shaped, smooth or sometimes with a small lateral basal cusp on either side. The first dorsal fin spineless, placed 

 opposite the interspace between the bases of the pectoral and ventral fins. Lower ca/udal lobe la/rge. A heel along 

 the side of the tail. A pit at the base of the caudal fm. 



1. Lamna Spallanzanii, Plate CLXXXVI, fig. 2. 



Lamna punctata, Storer, Bost. Journ. Nat. Hist, ii, 1839, p. 534, pi. viii, f. 2, and Mem. Amer. Acad, vs., 

 1867, p. 225, pi. sxxvii, fig. 1 ; Dekay, New Tork, Fauna, Fish. p. 352, pi. Ixiii, f. 206 (not MitcheU) ; 

 Poey, An. Soc. Esp. v, p. 381, t. xiv, fig. 1. 



Oxyrhima Bpallamzanii, Bonap. Faun. Ital. Peso. t. cxxxvi, f. 1 ; Dumeril, Hist. Nat. Poiss. i, p. 408. 



Oxyrhina gomphodon, Miiller and Henle, Plagiost. p. 68, t. xxviii. 



Iswopsis BeJcayi, Gill, Ann. Lye. Nat. Hist. New Tork, vii, p. 409. 



Oxyrhina punctata, Dumeril, 1. c. p. 409. 



Lamna spallanzoMii, Gunther, Catal. viii, p. 390 ; Klunz. Fische Roth. Meer. 1871, p. 669. 



Snout pointed, angle of the mouth about midway between the nostril and the first gill-opening. 

 Gill-openings very wide. Teeth — l| on either side, awl-shaped, with sharp but entire lateral edges, and 

 destitute of basal cusps : the third on either side of the symphysis of the upper jaw smaller than those on 

 either side of it. Fins — the base of the first dorsal rather nearer the pectoral than the ventral fin. Pectoral 

 falciform, its inner being one-fourth of the length of its outer margin. Second dorsal and anal small, situated 

 opposite one another. The keel on the side of the tail commences anterior to the base of the second dorsal 

 and anal fins. Colowrs — gray, becoming lighter beneath. 



Habitat. — Eed Sea and Indian Ocean, also the Atlantic and Mediterranean. The figure is from one of 

 Sir W. Elliot's drawings, which was taken from an example captured at Madras. It attains to a very 

 large size. 



