THE MICROSAURIAN FAMILY SAUROPLEURID^. I63 



pleura) to which Cope (176) referred this species. The form is not a member of the 

 genus Sauro pleura, for reasons given below. 



The species of the genus Sauro pleura have a lanceolate head with homodont den- 

 tition or nearly so. The orbits are located well back in the skull. The form of the 

 body is elongate and slender and the limbs where known are long and attenuated. 

 The ventral scutellation consists of oat-shaped scutes arranged in a chevron series. 

 The form here described as Saurerpeton latithorax Cope has nearly the opposite of 

 all of these characters, and it is incongruous to locate the form under the former 

 genus. The skull of Saurerpeton latithorax Cope is broad and heavy. The teeth 

 are heterodont. The body is broad and stout and the limbs are of unusually 

 strong proportions. The character of the ventral armature is also of a very differ- 

 ent type. In Saurerpeton it consists of very broad imbricating scutes which form a 

 single piece across the abdomen and are angulated to form the chevron pattern 

 which is so common among the Stegocephalia. 



Sa«irerpeton latithorax Cope. 



Cope, Proc. Am. Phil. Soc., xxxvi, p. 86, pi. iii, fig. 4, 1897. 

 MooDiE, Jour. Geol., xvii, No. i, p. 80, fig. 23, 1909. 



Type: Specimen No. 4471, U. S. National Museum. 



Horizon and locality: Linton, Ohio, Coal Measures. Collected by R. D. Lacoe. 



This species is indicated by remains of the anterior half of a large amphibian 

 (plate 17) preserved on a block of bituminous coal from the Linton mine. The form 

 is unusual in the proportions of the head and the width of the thoracic region. In 

 these characters it stands alone among the Amphibia from this locality, where the 

 forms are for the most part of rather slender build and tapering, pointed head. 



The skull is represented in a fairly complete condition and shows the usual 

 stegocephalian arrangement of the skull elements, as well as the sculpturing of the 

 bones, which is similar to that found in other members of the Microsauria. The 

 skull is broadly rounded, with the posterior border incised, the broad tympanic 

 notches thus rendering the shape of the skull somewhat like that of the branchio- 

 saurs. The orbits are broad ovals and lie well forward in the skull. They are sepa- 

 rated by a space which is greater than the greatest diameter of the orbit. The 

 pineal foramen lies well back and is clearly indicated as a circular opening which 

 lies in the median suture in the posterior half of the parietals. The nostrils seem to 

 be elongate and have an oblique position, as is represented in the diagram (fig. 35) , 

 but this character is not ascertained definitely. 



The borders of the premaxillag and the anterior suture of the nasal can not be 

 determined, though they may have had some such arrangement as suggested. The 

 nasal is represented, so far as is determinable, by an oblong element lying between the 

 frontal and the anterior border of the skull. The f rentals are very large and form a 

 portion of the inner border of the orbit. The parietal is probably the largest bone 

 in the cranium and together the two elements form a large quadrangular space 

 in the posterior half of the skull. They inclose the circular pineal foramen. The 

 postparietal is a small element lying on the posterior border of the skull and with 

 the tabulare and a part of the supratemporal forms the projection. The prefrontal 



