NEW PERMIAN VERTEBRATES. 253 



positions they occupy with regard to the tarsus, so that the length 

 of the toes is quite certain. Those phalanges which cannot be 

 extricated from the matrix are shaded. In all probability the pha- 

 langeal formula is like that of the front feet ; certainly there can- 

 not be a greater number. 



Six genera of Permian reptiles, all from Texas, are referred by 

 Cope to the family Pariotichidae ; and, notwithstanding the dif- 

 ference in the teeth, I am disposed to add the seventh genus, 

 Labidosaurus, to the same family. They are defined by Cope as 

 follows : l 



1. Teeth on the maxillre and mandibles in a single series Labidosanrns Cope. 



Teeth in more than a single series 2. 



2. External nostrils inferior; mouth posterior in position ; mandible short and with a 



few acute teeth Hypnopous Cope. 



External nostrils lateral 3. 



3. Palatal and splenial teeth with compressed crowns 4. 



Palatal and splenial teeth obtuse, forming a grinding pavement ; median maxillary 



and anterior incisor teeth enlarged Pantylus Cope- 



4. Teeth equal, -acute hodecies Cope. 



Teeth increasing gradually in length anteriorly Captorhinus Cope. 



Teeth enlarged in the middle of the maxillary and anterior part of the incisor 



series Pariotichus Cope. 



The genus Hclodectes, provisionally placed in the Parioti- 

 chidas, is distinguishable by the two rows of teeth on the jaws, 

 the "bases of which are wide ovals, transversely placed." 



Isodectcs is figured by Cope as having the prefrontals and post- 

 frontals meeting broadly over the orbits, widely excluding the 

 frontals from the orbit. The skull, moreover, is much longer 

 than broad in the type species, /. megalops. Pantylns also has 

 the prefrontals and postfrontals meeting broadly as in Isodectes in 

 the type species, P. cordatns, which, moreover, has a rounded 

 muzzle, and is widely expanded posteriorly. Captorhinus has an 

 elongate, pointed skull, with the orbits twice the diameter of the 

 interorbital space. Hypnopous is wholly out of consideration be- 

 cause of the remarkable position of the nares. Assuming that 

 our species has more than one row of teeth on maxillae and man- 

 dibles, its exclusion from the labidosaurs is of course evident. 

 As that character cannot be determined save by the mutilation of 

 the otherwise perfect skull, the doubt must be left. By ex- 



1 Proc. Amer. Phil. Soc., XXXIV., 1895, p. 445. 



