58 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



canal, which, in one specimen (471), are remarkably complete and instructive. The 

 three specimens will be discussed separately, since they show different features. 



The impression of the larger animal (No. 803, Yale University Museum), which 

 is probably an adult, presents the following elements: the entire skull, both humeri, 

 impressions of posterior and anterior ventral armature, portions of the alimentary 

 canal, one femur, portions of a fibula and tibia, and the entire impression of the tail, 

 on which, as in Micrerpeton caudatum, there occur two definite dark lines, one begin- 

 ning at the tip of the tail and running obliquely along the tail to where the impres- 

 sion is broken at the anal region; the other beginning at a distance of 4.5 mm. from 

 the tip and running almost parallel with the median line. These two lines undoubt- 

 edly represent the lateral-line system. 



The skull is especially noted for its shortness and the great posterior width, as 

 well as for the almost entire absence of the tympanic notch. The pineal foramen is 

 located on a line with the posterior border of the orbits. The eyes themselves are 

 narrow and acuminate at each end, with a pronounced convexity inwards and a 

 flattening on the outer margin. They are located on the very border of the skull, 

 but relatively more posterior than in Micrerpeton. No sclerotic plates are evident. 

 The median suture can be indistinctly observed nmning the entire length of the 

 skull. The sutures bounding the outside of the frontals and the squamosals are 

 partially evident, but not satisfactorily preserved. The mandible is represented by 

 a mold which in wax impression shows short, stumpy teeth. 



Posterior to the skull at a distance of a millimeter there are two sharp impres- 

 sions which may represent the anterior edges of the interclavicle or they may be 

 branchial elements. They are distinctly curved, however, and probably represent 

 portions of the interclavicle. A wax impression does not show a discrete structure, 

 but the boundaries of some larger element. No other remains of the pectoral girdle 

 can be discerned. The humeri are short and relatively thick. Wax impressions 

 show them to have had truncate or slightly concave ends, thus indicating the 

 absence or slight development of the endochondrium. No other elements of the arm 

 are preserved. 



The impression of an elongate femur and the heads of the tibia and fibula of the 

 left side are preserved. 



The ventral armature is preserved in two small patches, and these show the 

 chevron-shaped rods to have been very fine — much more delicate than in Micrerpeton. 



The body impression is very instructive and interesting, both in showing the 

 form of the body and because in it are preserved the larger portions of the alimen- 

 tary canal. The form of the body can best be discerned by reference to the figures 

 (plate 3, figs. I and 2; plate 5, fig. i). 



The portions of the alimentary canal preserved consist of the greater portion of 

 the stomach, three coils or loops of the small intestine, the rectum, and a pit which 

 undoubtedly represents the anal opening. The anus is found at a distance of 16 mm. 

 from the tip of the tail and is somewhat removed from the body portion, as in mod- 

 em salamanders. On each side of the posterior end of the rectum there occur a pair of 

 enlargements which probably represent the oviducts at their posterior ends (fig. 1 5 , C) . 



