THE AMERICAN COAL MEASURES BRANCHIOSAURID^. 



59 



The tail impression is more acuminate than in Micrerpeton, but shows the same 

 structures as in that form, i.e., the lateral lines which have already been mentioned. 

 Micrerpeton was a more rapid swimmer than the present form on account of the 

 greater development of the tail. 



The second specimen of the species (No. 802, Yale Museum) shows much the 

 same character as the specimen already described, except that there are impressions 

 of small, blunt teeth on the mandible. The two humeri and the femur of the left 

 side are preserved and the interclavicle is represented by an identical impression, as 

 in the first-described specimen. The tail impres- 

 sion, though similar in form, does not exhibit so 

 much of the structure of the lateral lines (fig. 15, B). 



The matter of especial interest in connection 

 with this second specimen is the remarkably perfect 

 preservation of the alimentary canal, which is entire, 

 except for the very anterior end of the oesophagus. 

 The posterior portion of the oesophagus, which 

 measures 3.5 mm., is clearly preserved. Its anterior 

 end is thrown around posteriorly and indicates that 

 this end was loosened after death and became dis- 

 placed before fossilization. The length preserved 

 may represent the entire oesophagus. The oesoph- 

 agus is constricted before it enters the stomach, 

 which shows the usual curvature found in modern 

 salamanders. The stomach measures 6 mm. in 

 length by 2 mm. in breadth, and consists of a 

 single enlargement as in the modem Ambly stoma 

 punctatum. It increases in size somewhat toward 

 the pyloric end and then very gradually constricts 

 to the pylorus. Three divisions of the small intes- 

 tine can be seen. The most anterior one, corre- 

 sponding to the duodenum, is segmented, as though 

 the intestine had been filled with food before inter- 

 ment. The remainder of the intestine, correspond- „ . , ^, , 



... . „ orbit; i/, stomach; /, tibia and fibula. 



ing to the ileum, is looped in the form of two figures B. Type specimen of Amphibamus thora- 

 _ , . , • J -.v 1-1. i.- caius Moodie. Original in U. S. Na- 



8 which are superimposed, with the upper portions tional Museum, xl (For description 



of the 8 at right angles to each other. The rec- see p. 132.) 

 turn is clearly discernible, though its lower portion is somewhat obscured by having 

 the lower part of the upper loop of the intestine lying over it. The anus lies at a 

 distance of i .5 mm. posterior to the transverse line from the upper end of the femur, 

 and is quite well back on the tail, as in modem salamanders. In this specimen also 

 occur two oval bodies which may be identified as the lower ends of the oviducts, 

 thus indicating, in all probability, that the animal was a female. 



A dissection of several species of modem caudates has resulted in the discovery 

 that the adult condition of the alimentary canal of all the species dissected {Ambly - 



B 



Fig. 14. — Mazon Creek Amphibia. 



A. Third specimen of Eumicrcrpeton parvunt 

 Moodie, which exhibits the alimentary 

 canal well preserved. X 2. Original 

 in United States National Museum. 

 a, anus; /, femur; h, humerus; ic, inter- 

 clavicle; in, intestine; m, mandible; or. 



