EGERT0N ON PONDICHERRY FISHES. 169 



described. Of the various forms com- 

 prehended in this species, one fossil 

 most nearly approximates a tooth from 

 the Maestricht quarries. Its peculiar 

 distinctive features are, the larger size 

 of the lateral cusp, the greater breadth 

 and obliquity of the base, and the smaller 

 proportions of the principal cone com- 

 pared with the other dimensions of the 



tooth. When viewed in profile, the principal cone is straight and 

 narrow, and the cusp from its inward slope forms an acute angle 

 with the principal cone. Both surfaces are smooth and rounded ; 

 the inner are, as usual, rather more so than the outer. The tooth 

 is slightly oblique, but not so much so as the Maestricht specimen. 

 As this feature varies according to the position of the tooth on the 

 jaw, it is of little value. 



Otodus nanus Eg. — A single tooth in Mr. Kaye's collection, 

 referable to the genus Otodus, differs from the other 

 species of the same genus in its diminutive size. /? A 

 The central cusp is triangular, equalling in height K^? 

 the breadth of the base. It has a thick and 

 stunted aspect, being equally convex on either surface. It is in- 

 curved, and slightly obtuse at the apex. The lateral cusps are 

 short, wide, and blunted. 



Otodus divergens Eg. — An unique specimen in Mr. Cunliffe's 

 collection, although differing in some respects from the 

 general characters of the genus Otodus, has notwith- 

 standing more resemblance to this than to the squaloids 

 of any other genus. The central cusp, from its sharp, 

 flattened, and lanceolate form, resembles an Oxyrhina or 

 Lamna ; but the large development of the lateral cusps must ex- 

 clude it from those genera. From Odontaspis it differs in the 

 width and general character of the lateral cusps. The latter are 

 exact miniature representations of the principal cusp, and are so 

 placed upon the base as to slope outwards on either side. They 

 have each a small supernumerary point on the outer shoulder. 

 The tooth is slightly convex on both sides ; the point is somewhat 

 recurved ; and the edges of all the cusps are remarkably sharp. 

 This is a perfect and very interesting specimen. 



Otodus minutus Eg. — The, last specimen I refer to this genus is 

 of small size, not exceeding the dimensions of Otodus 

 nanus described above, yet of different form. The A | \ 

 principal cusp is more lanceolate, and the antero- L^g jj) v 

 posterior diameter is infinitely smaller, compared 

 with the height of the tooth. The profile is straight, not incurved 

 as in 0. nanus. The lateral cusp is small and blunt. A promi- 

 nent ridge borders the enamel at its junction with the base. 



Oxyrhina triangularis Eg. — It requires specimens of unusual 

 perfectness to enable the palaeontologist to dis- 

 criminate between the species of the genera Oxy- /[ 

 rhina, Lamna, and Otodus. The Indian teeth, ^-^ 



