94 Sir P. Egerton on Fossil Fishes from Southern India. 



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. The central cusp is triangular, equalling in height ^J^ /^ 

 the breadth of the base. It has a thick and stunted aspect, being 

 equally convex on either surface. It is incurved, and shghtly 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 notwithstanding 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 exclude 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 principal cusp is more lanceolate, and the antero- /L 

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



Oxyrhina triangularis, Eg. — It requires specimens of unusual perfectness to en- 

 able the palaeontologist to discriminate between the species of the 

 genera Oxyrhina, Lamna, and Otodus. The Indian teeth, being for /i 

 the most part imperfect, it is a matter of great difficulty and uncer- 

 tainty to decide to which genus many of them belong. The proposed arrangement 

 of species must, therefore, be considered as a mere approximation, or rather, per- 

 haps, as provisional, until more perfect specimens, or one more skilled in Fossil 

 Ichthyology, shall clear up the obscurity. Several smooth teeth in the Indian col- 

 lections are remarkable for their regular triangular form. They appear to have 

 been destitute of lateral appendages. The base in this species is broad, equalling 

 the total height of the tooth . The cone is flattened on the outer surface and rounded 

 on the inner. The enamel of the latter descends lower on the base at the sides than 

 at the centre : the line of boundary thus represents an ascending obtuse angle. 

 The teeth are more or less oblique according to the position they hold on the jaw. 

 It is one of the smallest species of the genus. 



