THE MICROSAURIAN FAMILY AMPHIBAMID^E. 



133 



Cephalerpeton ventriarmatum Moodie. 

 MOODIE, Kans. Univ. Sci. Bull., VI, No. 2, pp, 350-352, pi. I, fig. 4; pi. 7, fig. 2, 1912. 



Type: Specimen No. 796, of Yale University Museum. 



Horizon and locality: Collected at Mazon Creek in 1871, near Morris, Illinois. 



The remains on which the present species 

 is based consist of an almost entire skull, 26 

 consecutive vertebrae, both fore limbs, 20 ribs 

 preserved on the right side of the body, and a 

 portion of the ventral armature (plate 4, fig. 4). 



The skull is very broad posteriorly, its 

 width being one-third greater than its length, 

 with due allowance for crushing. A pineal 

 foramen is not preserved. The sutures bound- 

 ing the premaxillaries, the maxillae, the nasals, 

 the pref rentals, the f rentals, a portion of the 

 parietals, the squamosal, the supratemporal, 

 the quadrate jugal, and the quadrate (?) are 

 fairly well preserved. The arrangement of 

 these elements can be discerned by reference 

 to figure 29. The prefrontals are unusually 

 large and are triangular in shape. The supra- 

 temporal is also quite large. The surface of 

 the skull bones is smooth and there is nowhere 

 an indication of sculpture. 



Portions of 4 sclerotic plates are preserved 

 in the right orbit. These measure 0.5 by 0.75 



> i -> 



mm. The orbits are large and the mterorbital 



, . c 



space is less than the transverse diameter of 



tliA nrhi'r TrnVtppn tppth innarentlv nlenrn- 

 tne OrDlt. ,n, c 



dont, are preserved on the left maxilla. They 

 are short, sharply pointed, smooth, and unequal. The first 2 left maxillary teeth 

 from the anterior end are short; then follows a tooth which is one-third longer 

 than these two; the fourth tooth is somewhat shorter than the third; the fifth 

 and sixth are still shorter and are practically equal in size, though somewhat larger 

 than the first two. 



The right mandible is preserved almost entire, though so badly eroded that little 

 can be said of its structure. Impressions of 12 teeth are present on the mandible and 

 all are, apparently, equal. The cotylus seems to have been far posterior and an 

 angle of the mandible projected slightly back of the skull. 



There remain only a few indefinite impressions of the cervical vertebrae. The 

 union of the skull with the vertebral column is obscured and lost. Impressions of 

 the dorsal vertebrae are well preserved, and wax molds made from these show 

 the structure of the dorsal vertebrae surprisingly well. They are long and cylin- 

 drical, with the median portions slightly constricted by a deep pit on each side of 



t 



FJG. 29. Skeleton of Cephalerpeton ventriarmatum 



Moodie. x i. 



Pf, prefrontal ; d, clavicle ; m. mandible ; h. humerus ; 



_,-, j uga i; mx , maxilla; or, orbit; ph, phalanges 



of hand; *"""' P arietal : P> postorbital; r, 

 radius; s/>, sclerotic plates; , ulna; vs, ventral 



scuteite. 



