TERTIARY FISHES. 
3—243 
Punjab is a proof of tlie former existence in that area either of large tidal rivers, or 
of lakes which at one time must have communicated with the sea. 
Family II. LAMNIDJE. 
Genus. CARCHARODON, A. Smith.^ 
Characters. — Teeth large, flat, erect, regularly triangular, serrated. On each 
side of the upper jaw, at some distance from the symphysis, there are one or two 
teeth considerably smaller than the others. 
Distribution. — At the present day the genus is represented only by G. rondeletii, 
which appears to occur in all tropical and subtropical seas ; but it was extremely 
abundant in the tertiaries, ranging from the lower eocene upwards. 
Carchakodon. sp. 
(From the SiwaliJcs of Pegu.J 
History. — The specimen forming the subject of this notice is described for the 
first time. 
Tooth. — The tooth represented from the convex surface in plate XXXV. fig. 8 
was obtained by Mr. W. T, Blanford, from the Siwaliks of Pegu, British Burma. 
The writer has been unable to identify this specimen with any of the teeth of 
C. rondeletii or of the larger G. megalodus : it agrees, however, very closely in size 
and contour with teeth of C. sulcide^is., Ag., from the Red Crag, but the serrations 
are finer. Other specimens are required before the affinities of this form can be 
determined ; but the specimen is interesting as indicating that during the pliocene 
period Pegu, as at the present day, was traversed by the numerous outlets of the 
Irawadi. 
Genus, non. det. 
Vertebrae. — The vertebra of a shark represented in plate XXXVII. figs. 9, 9a, 
is one of two similar specimens in the Indian Museum obtained from the Siwaliks of 
Perim Island. They agree very closely with the vertebrm of Lamna cornubica^ and 
not improbably belong either to Lamna or Garcharias. 
Section II. BATOIDEI. 
Family. MYLIOBA TIDHd. 
Genus. MYLIOBATIS, CuvieP {ex Dum^ril). 
Characters. — Teeth hexangular, large, flat, tessellated : those in the middle mucli 
broader than long ; several narrower series on each side. In very young examples 
the median teeth are regularly hexagonal, and not larger than the others. 
Distribution. — Seven existing species are known,® one of which is almost cos- 
mopolitan ; while of fossil forms a very large number have been described. Signor 
IsseP gives a list of forty-two species, and by adding descriptions of four new ones, 
1 In Muller and Henle’s “ Syst. Beschreibung. d. Plagiostomen,” p. 70 (1841). 
2 “ Regne Animal,” 1st ed. vol. II. p. 137 (1817). 3 Gunther ” Catalogue of Fishes,” vol. VIII. pp. 488-492 (1870) . 
i ‘Ann. Mus. Nat. Genova.’ vol. X. jjp. 313-340 (1877). 
