74 PERMO-CARBONIFEROUS VERTEBRATES FROM NEW MEXICO. 



The skull, while in most excellent preservation so far as its shape and absence 

 of distortion or loss of parts are concerned, will not permit the determination of 

 the sutures with any degree of certainty. Certain lines, by their symmetry on the 

 two sides, seem in much probabiHty to indicate sutures, but it is quite impossible 

 for any one to say with certainty that they really do so without the corroboration of 

 additional material. These lines are indicated by dots; those of the face and upper 

 side seem very probable; the others are more doubtful (fig. 46). 



Dentition: On the right side of the specimen the maxillary teeth are all, or 

 nearly all, shown clearly; those of the mandibles are more obscure. There are 

 four premaxillary teeth, if the division between the maxilla and premaxilla is 

 where it is assumed to be, below the back part of the naris. Back of these four 

 teeth there are definitely nine or ten on the maxilla in front of the orbit. These 

 teeth are not nearly so broad at the base as they were figured by Case ; they do not 

 differ much in size, though the median ones are the longest and largest. Back of 

 these teeth there are four or five, possibly more, extending at least as far as the 

 middle of the orbit; they are of smaller size. Broom criticizes Case's interpreta- 

 tion of the maxillary teeth, but his own is no better; there are not nearly so many 

 as he figures, and they extend much farther backward. 



In the closely articulated position in which the mandibles are preserved in 

 this specimen it was impossible to ascertain the most essential characteristic of the 

 genus, the palatal and mandibular teeth. In order to determine their extent and 

 position a section nearly 2 inches in length was smoothly sawed from the right 

 mandible; and this section enables one to determine with certainty, not only the 

 presence of such teeth as were described in the genotype, but also their position. 

 In this section of the mandible as separated from the pterygopalatine, numerous 

 round teeth are seen, as also those of the opposing surface, the two sets attached 

 to their respective bones in a plane divergent from the vertical by about 45 degrees, 

 as shown in the figure of the front end of the section (fig. 46 a, a). The palatine 

 and splenial teeth have hitherto been supposed to be placed more nearly horizontal. 

 On the outer side, the stout and rounded upper border of the dentigerous ptery- 

 goid plate is seen just above the coronoid, where it joins the jugal. From this 

 junction the border is directed backward and downward for more than two-thirds 

 the distance to the articulation of the quadrate with the mandible. The apparent 

 fusion of the pterygoid with the jugal would suggest the presence of a transverse 

 bone. So far as the teeth are visible in the section broken away from the ptery- 

 gopalatine plate, they seem to be quite like those described in the following species. 

 The narrow space between the mandibles below does not permit the preparation of 

 the palatine region, especially so as posteriorly the region is more or less occluded 

 by a fragment of the vertebral column. 



Edaphosaurus novomexicanus, n. sp. 



A somewhat crushed specimen, discovered by Dr. v. Huene in the vicinity of 

 Arroyo de Agua, New Mexico, may be referred provisionally to a new species. 

 Although somewhat fragmentary, the specimen is of importance as furnishing for 

 the first time indubitable evidence of the relationship of Edaphosaurus and Naosau- 

 rits. The specimen consists of the skull and a connected series of fifteen vertebras, 

 together with the two incomplete scapulas, the right clavicle and a part of the left 

 one, the left clei thrum in articulation with the scapula, a number of ribs, a humerus, 

 and a radius. Some of the vertebral spines had been weathered out of the matrix, 

 and the pieces into which they were broken can not be reunited, because of the 

 absence of many. 



