154 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



imen, but as there is a considerable vacuity behind 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 amphibian snake. 



Phlegethontia linearis Cope. 

 Cope, Geol. Surv. Ohio, ii, pt. ii, p. 367, pi. xliii, fig. 2, 1875. 



Typ>e: Specimen in the American Museum of Natural History. 



Horizon and locahty: Linton, Ohio, Coal Measures. 



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

 the length is not readily ascertained. There is an outline of a triangular object 

 which may represent the skull of this specimen, although it is so far removed from 

 the vertebrae that there is some doubt as to whether it belongs with the vertebrae 

 or not. Indeed, there is even doubt whether it is a skull. The vertebrae have 

 longitudinal diapophysial keels, and have a zig-zag interlocking of neural arches. 

 The latter are distinctly turned outward. The vertebrae are very numerous, and 

 the tail very attenuated. The number preserved is about 60. The total length of 

 the coils unwound is about 295 mm., or 11 coils in 8 lines; but there are interrup- 

 tions not measured and confusions not unraveled. 



This is the most elongate and slender of all the species of the Carboniferous 

 Amphibia. The vertebrae are apparently ribless and there are no evidences of 

 limbs or pectoral plates. It may be said that the body consists entirely of skull 

 and vertebrae. 



Measurements of the Type of Phlegethontia linearis Cope. 



Entire length of skull (?) i8 mm. Length of single vertebra 2.50 mm. 



Width of same 8 mm. Height of vertebra 1 .50 mm. 



Length of vertebral column as preserved. . . 295 mm. Estimated length of body 15 in. 



No. 8370 G, American Museum of Natural History, shows a few vertebrae. 



Phlegethontia serpens Cope. 

 Cope, Geol. Surv. Ohio, 11, pt. 11, p. 367, pi. 32, fig. 2, 1875. 



Type: Specimen No. 1102 G, American Museum of Natural History. 



Horizon and locality : Linton, Ohio, Coal Measures. 



This amphibian is much larger than the last, approaching nearly in its dimen- 

 sions the Molgophis macrurus. It is represented by a series of 22 vertebrae, which, 

 like those of Phlegethontia 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 the last of the 22. 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 indistinguishable. They are connected 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, 3 lines. 



