PART 1.] Lydehker: Vertehrata from Tertiaries and Secondaries of India. 41 
in some respects to Sgloeosaurus and Iguanodon of the Wealden period, suggests that the 
Larneta group is not far removed from the lower cretaceous period—a view which would 
agree with their generally accepted position in the geological series. 
I have lately found in the Indian Museum a considerable series of caudal vertebrae of 
this genus, which were collected by Mr. W. T. Blanford in the Lametas of Plsdura; they 
are somewhat less compressed than the described specimen : and are accompanied by copro- 
lites, and some portions of the carapace of a Cheloman. I shall hope subsequently to give 
figures of the more perfect specimens. The vertebra and femur referred to by Mr. Hislop 
in the twentieth volume of the Journal of the Geological Society (p. 282) probably belong 
to this genus. 
MEGALOSAURUS, Sp. 
the fourth volume of the “ Memoirs of the Geological Survey of India” (p. 128), 
Mr. H. F. Blanford announced the occurrence of the remains of this genus in the Arrialur 
group of Trichinopoli (Upper Cretaceous); this announcement, however, does not seem to be 
generally known, as Professor Phillips in his “ Geology of Oxford ” (p. 196), in speaking of 
the distribution of Megalosaurus, makes no mention of its occurrence in India; for this 
reason I have introduced the genus here. 
The specimen on which Mr. Blanfor-d’s determination was made is the greater portion 
of a (probably) lower tooth; this tooth is laterally compressed, the anterior border is convex 
and the posterior concave, both produced into trenchant edges and marked by fine serrations > 
the transverse section is somewhat pear-shaped, the broader portion being in front. The 
height of the portion of the tooth remaining is 1'8 inches ; the antero-posterior diameter of 
the base - 91 inch, and the transverse diameter '4 inch. 
The tooth in form and size is almost identical with the teeth of Megalosaurus BucMandi 
of the Stonesfield and Portland oolites, the only difference being that the posterior border of 
the Indian tooth is rather straighter than that of the English species. 
In England the genus Megalosaurus ranges from the Lias to the Wealden, and is 
therefore chiefly characteristic of the Jurassic period. In India, as we said, it occurs in 
rocks, of which the marine mollusca fauna is homotaxically equivalent to that of the upper 
cretaceous rocks of Europe. This instance should make us extremely cautious in correlating 
the horizons of Indian and European rock-groups upon the sole evidence of land animals. 
As in many other instances in India, the land flora or fauna (exemplified in this case by 
Megalosaurus) of' a group of rocks, indicates a lower homotaxis for the group than does 
the marine fauna. This anomaly is probably to be explained by the greater similarity of 
physical conditions, and the consequent greater facility for migration in the ocean than on 
the land (to say nothing of the insulation of parts of the latter), by which the organised 
products of the former would sooner arrive at a new station than those of the latter ; the 
assumption in this case being that the wave of migration has travelled eastwards. 
Further remains of the Indian form are required to establish its specific distinctness ; 
the tooth will subsequently be figured. 
Plesiosaurus Indicus, n. sp. nobis. 
I have already recorded* the occurrence of a species of the above genus from the 
Umia beds of Each. On further examination, I now find that the specimen of the symphysis 
of a mandible, on the evidence of which the announcement was made, differs both in 
size and in the direction of the alveoli of the teeth from the mandible of Plesiosaurus 
dilichodeirus from the English Lias; it also differs, as far as I can make the com- 
* I’.ee. Geol. Surv., India, Vol. IX, p. 154. 
