6o 



AMPHIBIA AND PISCES OF THE PERMIAN OF NORTH AMERICA 



Genus ALEGEINOSAURUS nov. 

 Alegeinosaunis aphthitos sp. nov. 

 Zatrachys, Bull. Am. Mus. Nat. Hist., vol. xxiii, 1907, p. 665. 



Type: The anterior part of a skeleton, lacking the skull. No. 4756 Am. 

 Mus. Nat. Hist. 



Original description: "The shoulder-girdle is complete, but the bones of 

 the right side are in part covered by the bones of the right leg and foot which 

 have been thrown up and back in process of fossilizing. 



Fig. 12. — Alegeinosaurus aphthitos. No. 4756 Am. Mus. 



A. A fragment showing clavicle, scapula, cleitbrum, and some of the ribs of left side. X f . 



B. Left half of same fragment shown in A, showing fore leg and foot. X !■ 



C. Anterior view of neural spine of a dorsal vertebra with overlying dermal plate. X |. 



"The scapula resembles that of Eryops; the shaft is elongate and slightly 

 broadened at the distal end. There is a deep and well-formed cotylus, but 

 there is no trace of separate coracoid, procoracoid, or epicoracoid. 



"The interclavicle is roundly shield-shaped, without any posterior 

 prolongation. On the center of the lower face there is a prominence, with 

 articular edges for the inner edges of the clavicles. 



"The clavicles have the anterior end flat and roughly diamond-shaped, 

 with thin edges. The lower part of the inner edge articulates with the prom- 

 inence on the lower face of the interclavicle, and the upper part of the 

 edges meet above the articulation with the interclavicle. The shaft is 

 bent at an angle of about 45° to the anterior end. The section of the clav- 

 icle is like a capital L turned on its side. The long part of the L lies hori- 

 zontally and the short part is turned downward and covers the outer edge 

 of the cleithrum. The distal end reaches nearly to the posterior end of the 

 scapula. 



" The cleithrum: The posterior end is thin, wide, and closely applied to 

 the surface of the scapula; it quickly contracts to a narrow and high ridge 

 on the surface of the scapula near the upper edge. The anterior end extends 

 as far forwards as the cotylus of the scapula. 



"The humerus has the form common to the amphibia of the Permian; 

 the distal and proximal ends stand at an angle of about 45° to each other, 

 and a strong deltoid process and ridge reach nearly to the middle of the 



