148 



THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



This species is established by remains of 2 individuals, one embracing 16 and 

 the other 14 vertebrje, with ribs. The neural arches, viewed from above, have a 

 V-shaf>ed outline posteriorly, from the fact that the broad zygapophyses meet on the 

 median line and spread out distally over the broad anterior ones adjoining. The 

 latter appear to be somewhat concave and to border the former exteriorly as well as 

 inferiorly. The base of the neural spine extends to the posterior emargination, 

 but not quite to the anterior. The breadth of the dorsal vertebrae above is equal 

 from the emargination behind to the anterior margin of the anterior zygapophyses. 



The ribs are long for an amphibian, but not long for a reptile. They are well 

 curved, chiefly near the proximal extremity. The longest found, measured by a 

 cord, equals two and two-fifths vertebrae. These vertebrae, measured along the 

 median line above, equal 11 lines; one of these is 3.6 lines in width above. This 

 animal has been, like Amphiuma, a snake-like amphibian, but 

 was probably still larger. How near the affinities to this 

 genus may be can not now be determined, owing to the want 

 of many important parts of the skeleton, but it differs in the 

 important feature of large, well-developed ribs. The size of 

 the vertebrae would indicate a body of the size of the com- 

 mon rattlesnake (Crotalus horridus) and too large for Brachy- 

 dectes newberryi, which is only known from jaws. 



Molgophis brevicostatus Cope. 

 Cope, Geol. Surv. Ohio, u, pt. n, p. 369, pi. xliv, fig. i, 1875. 

 MooDiE, Proc. U. S. Nat. Mus., 37, p. 27, 1909. 



spine 



Bibi. 



Centrum 



Type: Specimen No. 8341 G, Amer. Mus. of Nat. History. 



Horizon and locality: Linton, Ohio, Coal Measures. 



Represented by portions of the vertebral column of several 

 individuals. One of these includes 9 pairs of ribs, with verte- 

 brae, and another 13 pairs. The vertebrae are subquadrate in 

 section, and the concavity of the two articular faces is not 

 deep. They support strong lateral ridges separated by deep 

 concavities. The heads of the ribs are somewhat contracted, 

 and the shafts present outward a tubercular angle at a dis- 

 tance of one-fourth the length from the head. The remaining 

 part of the shaft is stout, nearly straight, and gradually con- 

 tracts to an obtuse extremity. It possesses a narrow medullary cavity. In none 

 of the specimens is there any trace of abdominal armature, but abundant remains 

 of the contents of the abdominal cavity, in proper position, are preserved on the 

 blocks. This species is more massive than Molgophis macrurus, and the ribs are 

 shorter, thicker, and less curved. 



Ventral scutellae are present in one specimen of this species. There are a number 

 of specimens. They have the following numbers at the American Museum: 158, 

 HOC G, no number, 8341 G (type), no number, 8466 G; and 4477 in the IX. S. 

 National Museum. 



Fig. 32. — Drawing from 

 Cope's figure of Molgo- 

 phis brevicostatus Cope. 

 X0.5. 



