NO. 1696. AIR-BREATHING VERTEBRATES— MOODIE. 21 



The specimen is embedded on a small slab of soft coal from Linton, 

 Ohio. It is Cat. No. 4405 of the U. S. National Museum collection. 



ERPETOSAURUS MINUTUS, new species. 

 Plate 8, fig. 1. 



The genus Erpetosauriis will be more fully characterized else- 

 where. Suffice it to say here that it is erected to include certain 

 members of the genus Tvditanus. The species Erpetosaurus mhiutus 

 is the smallest of the genus so far known. The specimen on which 

 the species is based is composed of the greater portion of a small 

 skull preserved in the hard shale from Cannelton, Pennsylvania, 

 and was collected by Mr. R. D. Lacoe, of Pittston, Pennsylvania. 

 The characters of the specimen had not been previously determined, 

 since the museum label and number had partially obscured the snout 

 of the skull. The skull is very small, but has the form assumed by 

 other members of the genus. At first sight the specimen looks like 

 a broken scute of some large form. Closer inspection, however, 

 revealed the two impressions representing the orbits, and a Zeiss 

 binocular revealed the characters. The enlarged photograph plate 8 

 (fig. 1, X 5) shows the structure of the skull. The large size and 

 anterior position of the orbits, the character of the sculpturing, the 

 presence of a slight posterior table to the skull, as in Erpetosaurus 

 {Tnditanus) tahulatus Cope, are the characters on which a specific 

 diagnosis is possible. The specific characters which distinguish this 

 form from the E. tdbulatus Cope, are the slight development of the 

 posterior table, the more delicate form of the sculpturing, the more 

 posterior position of the orbits, and the varying shape assumed by 

 the parietals in the two species. Any one of these characters would 

 be valid as a specific character. The pineal eye is indistinct, but is 

 observed to lie in the broken tract in the median line of the skull 

 in the middle of the portion posterior to the orbits. The interorbital 

 width is equal to the width of each orbit. The orbits themselves are 

 slightly oval and not round as in the case of E. tahulatus Cope. 



The skull elements are sculptured with sharp radiating grooves 

 and ridges, and on the supraoccipitals and epiotics the grooves take 

 the form of pits in a row, which undoubtedly represent the occipital 

 cross-commissure of the lateral line system first observed by Andrews 

 in the skull of C evaterfeton galvani Huxley. The supraorbital canal 

 is represented by a slight elongate depression observable over each 

 orbit and extending, in one case, for some 5 mm. The presence of 

 the circular arrangement of the lateral line canals in the jugal region 

 is suggested by the depression on the left of the photograph on the 

 posterior edge of the squamosal. 



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

 enough, just as it is in Erpetosaurus tahulatus Cope. In the re- 



