628 



PKOF. H. 6. SEELEY ON 



[Aug. 1900, 



extremity of the bone. There is an ossification behind and below 

 the posterior extremity of the staff, which is of small size, imperfectly 

 exposed. It may be the extremity of a small sternum : a sternum 

 is found in Anomodonts. 



Its resemblance to the interclavicle of Saurosternon, which is 

 an Anomodont, had not escaped the notice of Prof. Wiedersheim. 

 It differs from the interclavicle of Echidna in the longer staff, and 

 less expauded extremities of the bone. The staff is not developed 

 in Eryops. 1 



The clavicles have not been recognized. 



Fig. 3. — Portion of the shoulder-girdle of Aristodesmus Rtitimeyeri. 

 (Nat. size.) 



Transverse bar of 

 the interclavicle 

 in front of the 

 border of the 

 precoracoid. 



The scapula has been placed in this 

 position, to show its relation to the 

 humeral articulation ; but it extends 

 dorsally over the coracoids, as pre- 

 served, and rests obliquely upon the 

 ribs. 



? Cervical 

 rib3. 



(b) The Precoracoid and Coracoid Bones. 



The Anomodontia are the only group of reptiles in which the 

 precoracoid is developed in a disc-like shape, similar to the coracoid 

 bone in form. In this fossil they are slightly separated one from 



1 The reputed sternum of Platypodosaurus inay be an interclavicle without 



