EEPTILIA OF KIRTLAND FORMATION GILMOEE 



183 



There are seven neurals of the usual coffin shape, the seventh being 

 much reduced in size, subelliptical in form. Table 5 gives the 

 dimensions of these bones. The preneural cannot be differentiated. 



Table 5. — Measurements of neurals of Aspideretes ovatus 



' Estimated. 



The nuchal is missing, but it quite evidently protruded prominently 

 from the front border. The form of the costals is well shown in 

 figure 15. The eighth pair of costals meet on the median line. It is 

 also possible that the seventh pair may meet on the median line for a 

 portion of their width. 



In the ovate form of the carapace this species has a resemblance 

 to Aspideretes vegetus but is distinguished by differences in the 

 sculpture and presence in the latter of numerous longitudinal welts 

 on the carapace. 



ASPIDERETES VORAX Hay 



Figure 16; Plate 18, Figltre 2 



A specimen (U.S.N.M. no. 12988) consisting of the anterior third 

 of the carapace is identified as belonging to Aspideretes vorax Hay. 

 The assignment of any specimen to this species must to a certain 

 extent be provisional because of the scanty nature of the type, which 

 consists of a nuchal and costal fragments. The close resemblances in 

 size and form of the present nuchal to that of the type, however, seem 

 to leave little chance of their not being cospecific. If this assign- 

 ment is correct, this specimen is of no little interest in contributing 

 to a better understanding of this little-known species. 



The specimen was collected by G. F. Sternberg from the Kirtland 

 formation, 3 miles northeast of Hunter's Store (Bisti P. O.), SWi/4, 

 T. 24 N., E. 13 W., San Juan County, N. Mex., in 1929. 



U.S.N.M. no. 12988 consists of the almost complete anterior third 

 of the carapace anterior to the suture for the fourth costal. The 

 front of the carapace is quadrangular, slightly excavated, and curved 

 upward over the neck. The nuchal projects but slightly beyond the 



