42 
Records of the Geological Survey of India. 
[vol. x. 
parison, from other described species of the genus; all the cretaceous and most of the 
oolitic species of English Plesiosaurus, however, are described from teeth or vertebrae only ,* 
so that, there is a possiblity of our species being identical with one or other of these forms. 
I have, however, thought it, best to give the Indian form a distinct name, if only to 
mark the locality from which it was obtained, and I propose to call the species P. indicus; 
no more accurate definition, however, can be given than that published in the first notice. 
A species—P. Australis —has been described by Professor Owen from Australia, so that 
we now know that the genus had wide distribution in space as well as in time. 
Pachygonia inctteva. — Huxley. 
This species of Labyrinthodont was described by Professor Huxley(f) from the Panchet 
group of rocks upon the evidence of a portion of a mandible wanting the extremity of the 
dentary piece; the jaw is characterized by carrying a row of minute teeth, which in cross 
section are transversely elongated. Among some specimens more recently acquired from the 
same group of rocks, I have found a part of a symphysial end of a left ramus of the mandible 
and a detached tooth of a Labyrinthodont, which belong to this genus. The mandible 
carries on its outer border a row of small, transversely, elongated teeth, from the form of 
which, and from the resemblance of the sculpture on the outer surface of the jaw to 
the same part in tho type-specimen, I have referred the new specimen to Pachygonia. 
At the anterior extremity of the specimen, and placed somewhat internally to the outer row of 
teeth, there is one large conical tooth, longitudinally striated, and bearing the same relation 
and proportion to the outer row of teeth as does the similarly situated tooth in the jaw of 
Lahyrinthodon packygnathus, figured by Professor Owen in his Odontography (PI. 63, 
fig. 5). A section of an isolated large tooth, which agrees precisely in form with the 
attached specimen, shews that the arrangement of the folds of the cement and dentine is 
almost precisely similar to those in the tooth of Lahyrinthodon (Mastodonsaurus) jaegeri, 
as figured iu Plate 64 A of Professor Owen’s Odontography. I am not acquainted with the 
structure of the teeth of all other Labyrionthodonts, but those of two at least of the 
carboniferous genera ( Anthracosaurus and Arehegosanrus ) differ very markedly from those 
of the Triassic type genus ; in any case, the close resemblance in form of the symphysis of 
the jaw and of the structure of the tooth of Pachygnathus to the same parts in the jaw 
of the tj'pe genus Lahyrinthodon, which is confined to the Keuper in Europe, affords a 
strong confirmation of Dr. Peistmantel’s view, derived from the study of the flora, as to 
the homotaxis of the terrestrial forms of life of the Panchet group of rocks with those of the 
Keuper of Europe. 
Dicynodon oeientalis. — Huxley. 
In a recent paper in the Quarterly Journal of the Geological Society of London 
(Vol. XXII, p. 98.), Professor Owen expressed his opinion that the foramen in the 
humerus of Dicynodon orientalis , from the Panchet rocks, is probably homologous with the 
foramen of Cynodraco major described in that paper. The Professor was, however, unable to 
be positive in this assertion, owing to the imperfect specimens figured by Professor Huxley in 
his above-quoted memoir on tho Panchet vertebrate. From an examination of more perfect 
specimens now in the Indian Museum, I am enabled to state that the foramen in the 
* British Cretaceous Reptiles, Owen,—Palaiont. Soc. Phillips’Geology of Oxford, 
f Paleeontologia Indie <?., Ser. IV, Vol. I, p. 6. 
