12 



OLIVER P. HAY 



of the femur could rotate. If the femur was inserted as the writer 

 supposes it was, its pressure would have been exerted mostly against 

 the bony side-walls of the acetabulum and but little against the tissue 

 filling the inner opening. 



In his splendid monograph on Die Dinosaurier der europdischen 

 Triasformation Dr. v. Huene has presented numerous restorations 

 of the Triassic carnivorous dinosaurs (Pis. IC-CX). In order to 

 show the author's conception of their modes of progression, three 

 species, Plateosaurus reinigeri, TJwcodontosaurus antiquus and Anchi- 



FIG. 7 PROXIMAL END OF RIGHT FEMUR, WITH ITS CAP OF CARTILAGE, AND 

 HORIZONTAL SECTION THROUGH ACETABULUM. dd, SECTION OF ACETABU- 

 LUM; 00, LINE CORRESPONDING TO dd WHEN LEG IS THROWN FORWARD; 

 bb, LINE CORRESPONDING TO dd WHEN LEG IS. AT RIGHT ANGLES WITH BODY', 

 CC. LINE CORRESPONDING TO dd WHEN LEG IS THROWN BACKWARD. 



saurus colurus are restored each in two positions, walking on all fours 

 and on their hinder extremities only. Dr. v. Huene has the following 

 to say (p. 291) regarding the position of the hinder limbs: 



Das Femur passt in der Weise in den Acetabularschnitt, dass das ver- 

 breiterte medial abstehende Proximalende nicht transversal unter dem 

 Ileum liegt, sondern schrag nach vorn und medial gerichtet ist (daher 

 wendet sich auch das Knie etwas auswarts) . 



Notwithstanding this explanation, one is struck by the very mam- 

 mal-like position of the body and the limbs of these reptiles in the 

 quadrupedal pose. Elbows and knees are drawn well towards the 

 sides and the digits are directed straight forward. At least, the pose 

 of these restorations is quite different from that of any living reptiles. 



