64 REVISION OF THE PELYCOSAURIA. 



"As the teeth were worn away or broken off they were replaced by others pro- 

 duced at their inner side, as is indicated in the specimen by a young tooth, which is 

 situated internal to and is concealed by the largest mature tooth. The enameled 

 crowns of the fully protruded teeth are exserted at their base for several lines above 

 the alveolar border of the jaw. The)' are compressed, conical, and recurved, but com- 

 pared with those of Megalosaiirns they are not so broad, compressed, nor recurved, 

 and they are more convex externally and are less so internally. They resembled 

 much more in form those of the recent Monitor ornatus, but are less convex internally. 

 The transverse section of the crowns of the teeth, except that of the first, is antero- 

 posteriorly elliptical, with the inner side less convex, and the extremities acute and 

 in most instances slightly incurved. 



" The anterior and posterior acute margins of the crowns are minutely crenulated 

 and the crenulations commence just below the tip and descend as far as the enameled 

 base. In comparison with the teeth of Clepsysaiirus Pennsylvauicus^ those of the 

 fossil under examination are broader and more compressed, and except the first one 

 of the series, present an acute, crenulated margin anteriorly and posteriorly, whilst in 

 the former animal they are acute and crenulate only posteriorly. * * * 



" From the extraordinary relative depth of the dental bone above described to its 

 length, and from its northern locality I have proposed for the carnivorous lacertian 

 to which it belonged the name Batkyguat/nis boreal is.''^ 



The true position of this animal was recognized by v. Huene (103) and 

 independently b}' the author (34). It was either a large Dinietrodon or a 

 Naosatirus^ but it is impossible to say which. The Canadian geologists had 

 long recognized that the greater portion of eastern Nova Scotia and Prince 

 Edward Island was Permian and recorded the presence of the Triassic only 

 because of the presence of this animal, which was regarded by Leidy and 

 Cope as a Triassic Dinosaur. The recognition of its true position shows 

 that Triassic deposits do not occur in the region. 



TomiCOSauruS Sp. Gen. nov. (Plate 27, figs, s and g.) 

 Generic name on Cope's label. 



Type: Six imperfect vertebrae and the anterior end of a lower jaw. No. 2212 

 Am. Mus. Nat. Hist., Cope, coll. ; from Texas. 



The anterior end of the lower jaw is 35 mm. long and this appears to be about 

 one-half or one-third of the full length. The anterior end is swollen and there are 

 alveoli for three large teeth and one or two smaller ones. Posterior to the incisor 

 teeth are seven smaller teeth in sockets ; they are all recurved at the upper end and 

 are of about equal height. They are not crenate. The jaw is of small vertical height 

 and is rather thin. There is a deep groove on the inner side marking the position of 

 the splenial which is lost. 



The vertebrae are crushed so that the form of the centra can not be made out. 

 Seen from above they show the peculiar character of very wide expanse of both the 

 anterior and posterior zygapophyses, although the neural arch is not especially wide. 

 The neural spines seem to have been short. The length of nine vertebrae is 42 mm. 



It is impossible to locate this form. It may perhaps belong to the Bo/osanrid(Z, 

 but the general appearance indicates the Cotylosatiria less than the Pelycosaiiria. 



