THE MICROSAURIAN FAMILY TUDITANID^. I05 



The portion of the skull anterior to the orbits is wanting, curiously enough, just 

 as in Erpetosaurus tabulatns Cope. In the remainder of the skull, the post-parietals, 

 the tabulare, the parietals, the supra temporal, and a portion of the right frontal can 

 be detected, although the boundaries of but three can be accurately defined. The 

 depression boimding the anterior outline of the skull is taken to be the impress of 

 the mandible, in which case this structure would be of some depth, as in the case of 

 the mandible associated with E. tabulatns Cope, described below. 



This specimen is of interest in respect to the presence of the lateral-line canals, 

 its small size, and its generic identity with forms from Ohio. There is still another 

 form known from the Cannelton slates, described below as Erpetosaurus {Tuditanus) 

 sculptilis Moodie. 



Measurements of the Type of Erpetosaurus minutus Moodie. 



mm. mm. 



Length of skull 18 Length of orbit 4.5 



Posterior width of skull 17 Width of orbit 3.5 



Width of skull across orbits 14 Interorbital width 3.5 



Erpetosaurus sculptilis Moodie. 



Moodie, Jour. Geol., 17, No. i, p. 61, figs. 11, 12, 1909 {Tuditanus sculptilis). 

 Moodie, Bull. Am. Mus. Nat. Hist., xxvi, p. 347, 1909 {Erpetosaurus sculptilis). 

 Moodie, Proc. U. S. Nat. Mus., 37, p. 22, 1909 (describes pectoral girdle). 



Type: Specimen No. 12,315, University of Chicago, Walker Museum. 



Horizon and locality: Cannelton slates, Pennsylvania (Upper Freeport). 

 (Plate 18.) 



There is preserved in the collections of Walker Museum of the University of 

 Chicago a small amphibian skull pressed flat on a slab of slate from Cannelton, 

 Pennsylvania. It formed part of the Hall collection acquired by the University of 

 Chicago in 1908. 



The specimen presents only a portion of the skull and fragmentary pectoral 

 plates. The skull is wider than long and the muzzle is broadly rounded. The orbits 

 are narrow ovals and their posterior border falls on the transverse line dividing the 

 skull equally. The interorbital width is slightly greater than the width of the orbits 

 and about equal to their length. The posterior outline of the skull is somewhat 

 truncate, as in E. tabulatns Cope and other species of the genus. The distal 

 extremities of the quadrates do not project as far backward as do the supraoccipitals. 

 The skull roof is formed of the regular elements, except that a quadrate seems to be 

 indicated by a scale of bone on the posterior angle. The nostrils are oval and the 

 pineal opening is small. 



The premaxillae are apparently relatively large elements, though their bounda- 

 ries are not definite. The nasal is of an oblong shape and borders the frontal ante- 

 riorly. The frontal forms the whole of the interior border of the orbit and borders 

 the parietal broadly behind. The parietal is a large element and the pineal foramen 

 is inclosed in the median suture about midway of the parietals. The postparietal 

 is wider than long and with the tabulare forms the greater part of the posterior 

 border of the skull. The prefrontal (plate 18, fig. i) apparently forms the entire 

 anterior border of the orbit and sends an acuminate projection to the side of it. The 



