552 



THE AMEBIC AX NATURALIST [Vol. XLIV 



The character of this rugosity is certainly that of an 

 attachment for powerful muscles ; its position is substan- 

 tially that of the distinct process in the larger bipedal 

 dinosaurs ; while the surface where Dr. Hay would locate 

 the attachment is a surface of smooth bone. On the other 

 hand, the view of Marsh and Hatcher, apparently shared 

 by Holland, that the entire proximal-external angle, in- 

 cluding part of the rugose surface of the proximal end, 

 similar in character to the rest of the anatomical head or 

 articulating surface, is the great trochanter, appears to 

 be indefensible, and Dr. Hay's arguments conclusive as 

 against it. This view seems to have been founded on the 

 analogy with the proboscidean femur, carried further 

 than the facts warrant. But Dr. Hay's conclusion that 

 the femur of the Sanropoda represents a very early 

 stage in progressive adaptation of the limb from the 

 primitive swimming to the walking type, is not war- 

 ranted if Osborn's view as to the position of the tro- 

 chanter be correct, for as Hay rightly observes, in the 

 progressive stages of adaptation to upright carriage 

 this attachment moves up towards the head of the bone. 

 But the only semblance of argument that Dr. Hay offers 

 against this view seems to be the assumption that Diplo- 

 docus was more primitive than its Triassic predecessors. 

 The truth seems to be that the Sauropoda were highly 

 specialized as regards the adaptations for upright walk- 

 ing, but degenerate as regards the adaptations for bear- 

 ing great weight on the limbs. 



As to the aquatic habitat of the Sauropoda, Dr. Hay's 

 statement of the evidence can hardly be regarded as a 

 fair one, although he seems to be of the opinion that the 

 larger forms, at any rate, were secondarily aquatic. 



The ability of any large animal to walk about thus submerged must 



