ORDER CAUDATA DUMERIL, 1806. 71 



' ' The general appearance of the type of this genus is that of a Ptyonius, but the ventral 

 armature is different from anything observed in the known genera of this group. The 

 larger external scuta are like those of the species of Colosteus (Sauroplcura) , but their series 

 have a different direction. The inner chevrons are those of many other genera" (123). 



Hyphasma laevis Cope. 



COPE, Proc. Acad. Sci. Phil., p. 16, 1875, 



COPE, Geol. Surv. Ohio., 11, pt. n, p. 387, pi. 37, fig. j, 1875. 



Type: Specimen No. 9023 (in counterpart), American Museum of Natural 

 History. 



Horizon and locality: Linton, Ohio, Coal Measures. 



"In the only known specimen the vertebras have low and squarely truncate neural 

 spines near the head, and some distance anterior to the tail they are quite conspicuous 

 and delicately line-grooved. The body is slender and probably limbless. The thoracic 

 scuta are large and close to the head; the median is produced at both ends, but chiefly 

 anteriorly while the lateral are narrow; all are without sculpture The head is seen from 

 below. The mandibular rami are not so slender as in most species of Ptyonius, but are 

 rather stout. They are a little incurved distally, so that the form of the muzzle is somewhat 

 narrowed, but not produced. The teeth are not visible. Ten rows of the outer layer of 

 scuta in 0.005 m -" ( I2 3)- 



The specimen is very indistinctly preserved and the characters given by Cope 

 can not all be made out. It is puzzling to see just on what he bases his conclusion. 

 It is possible that the specimen is a poorly preserved Ptyonius. The outlines of the 

 vertebrae are so indistinct that I am uncertain about them. In certain lights there 

 appear to be regular impressions which resemble the spines of the vertebras of 

 Ptyonius, but they are doubtful. The skull appears totally distinct from any 

 known species of Ptyonius, but it is very imperfect. The condition of the pectoral 

 elements is very uncertain and I can not be sure that what Cope described as tho- 

 racic "scuta" are such. The interclavicle, however, is clearly preserved as a diamond- 

 shaped structure. It is almost smooth, with a few faint radiating lines near the base. 

 It measures 5 mm. in greatest breadth by 8 mm. in length. 



MEASUREMENTS OF THE TYPE. 



mm. mm. 



Length of specimen as preserved 04 Length of median thoracic scuta 10 



Length of skull 15 Width of same 4 



Greatest width of skull 8 Width of clavicle 2 



Width of body 8 Length of mandibular ramus . .... 12 



Length of 7 cervical vertebras 15 



