EXTINCT BATRACHIA. 367 



the skull of the specimen, it may be that these were lost with other 

 parts. Chevron bones are not observable on the caudal vertebrae. This 

 form is a true Batrachian snake. 



Phlegethontia linearis, Cope (species nova). 



In the only specimen the dorsal vertebrae are much involved anteriorly, 

 so that the length is not readily ascertained. The entire outline of the 

 skull is preserved ; it is elongate-triangular in form, with the angles of 

 the mandibles produced backward, and the outlines of the rami a little 

 convex. Nothing definite remains as to sculpture or dentition. The 

 vertebra? have longitudinal diapophysial keels, and have a zig-zag inter- 

 locking of neural arches, probably by an external zygosphen above the 

 zygapophyses. The latter are distinctly turned outward. The vertebrae 

 are ver}^ numerous, and the tail very attenuated. The total length of 

 the coils unwound is about .295 m., or eleven in eight lines; but there 

 are interruptions not measured, and some confusion not unraveled. Num- • 

 her of dorsal vertebrae in .005 m., two; of distal caudals, three and a half; 

 length of cranium, .022, width behind, .009. Its size is about that of the 

 skull of Ptyonius Marshii, Cope. The slenderness of the body may be 

 estimated from the diameter of the dorsal vertebrae, .0023 m., and of the 

 caudals, .0014. The whole number of vertebrae preserved is fifty-six. 

 Another specimen, embracing fifteen vertebrae, without processes, or ribs, 

 or other parts, resembles this species. There is nothing additional to be 

 learned from it. 



Phlegethontia serpens, Cope (species nova). 



This Batrachian is much larger than the last, approaching nearly in 

 its dimensions the Molgophis macrinus. It is represented by a series 

 of twenty -two vertebrae, which, like those of P. linearis, are devoid of 

 ribs, abdominal armature, dilated neural spines, etc. The series, when 

 complete, must have been very long, as there is little difference in size 

 between the first and last of the twenty-two. They are marginate fore 

 and aft, and much contracted medially, owing to the transverse expanse 

 of the diapophyses. There may be, indeed, a diapophysial element 

 beneath these, but if so, the two are undistinguishable. They are con- 

 nected by longitudinal impressions, indicating the existence of the 

 tendinous bands in the longitudinal muscles seen in Amphiuma, or the 

 osseous spicules seen in the same situation in birds. The neural spines, 

 as indicated by their narrow bases, occupy the length of the neural arch, 

 and remind one of Amphiuma. Width of one of the vertebrae, three lines. 

 This species appears to be rare at Linton. 



