THE AMERICAN COAL MEASURES BRANCHIOSAURID^. 



65 



saurians in this respect. The ribs show a progressive decrease in length from the 

 cervical region to the point of 'their disappearance on the tail. 



The pectoral girdle is represented by two elements, one of which is certainly 

 the right clavicle, and the other is possibly the left clavicle, though its form is some- 

 what distorted by pressure. Both elements are in the form of an elongate spatula 

 with the dorsal surface greatly concave and the inner end acuminate. 



The right humerus is imperfectly preserved, though the impression allows one to 

 gain an exact idea of its form. It lies under the right clavicle. Its ends are truncate 

 with a contracted shaft and expanded extremities ; the bone was apparently hollow. 



*^* 



Fig. 15. 



A. Impression of Erierpeton branchialis Moodie. bb, basibranchial ; hyp, hypohyals; m, mandible; 



d, body impression. X 3. 



B. Eumicrerpelon parvum Moodie. a, anus;/, femur; h, humerus; in, intestine; /, liver; st, stomach; 



r, radius; u, ulna. X 3.3. 



C. Larger specimen of Eumicrerpelon parvum Moodie. 



in, intestine; ml, median lateral line; si, stomach. 



D. Skeleton of Erpelobrachium mazonensis Moodie. d, clavicle; h, humerus; r, radius; sc, scapula; 



«, ulna. X 2. 



E. Rib of Mazonerpeton costalum Moodie. X 2.5. 



Originals in the Yale University Museum. 



a, anus; d, dorsal lateral line; h, humerus; 

 X 2.6. 



In another nodule (No. 804, Yale Museum) there is a single bone preserved which 

 resembles, to a great extent, a rib of the present species (fig. 15, E), although some- 

 what larger, and it has been provisionally identified as such. The element is very 

 slightly curved, but shows the expanded head of the rib of this species. 



