M. Talbot — Podokesaurus holyolcensis. 



471 



Description. 



In the description which follows these features are to he 

 noted : Light construction — hollow bones ; slender, straight 

 femur ; position of fourth trochanter ; position of fibula, lying 

 close to the tibia ; great length of tibia and metatarsals ; small 

 humerus ; narrow shaft of ischium ; great length of pubis ; 

 length of vertebrae. 



Forelimb. — The humerus (fig. 1, H.)* is a very delicately 

 shaped bone, 42 mm long (not cjuite half the length of the femur), 

 slender and well rounded, with high radial crest. The proxi- 

 mal end shows a slight constriction above the crest and below 

 the bone tapers gradually to a diameter of 3 mm at the distal 

 end. Measured through the crest it is 8 ram . There is a trace 

 of the impression of the radius or ulna just beyond the distal 

 end. 



In the scapular region is a broad, flat bone, lying vertically 

 in the rock, but twisted on its long axis at a right angle, mid- 

 way of its length (fig. 1, S.). This bone has a length, as 

 shown, of 20 mm and a width of at least 3 mm . Lying near its 

 proximal end is another flat bone, 8 mm long by 5 mm wide. 

 These may be three separate bones, more or less firmly united 

 in the living animal. Further development is necessary, how- 

 ever, to bring out their outlines and their relation to each 

 other. 



Rindlimb. — The femur (fig. 1, R. F. and L. F.) is slender 

 and nearly straight with thin walls. The bone is expanded on 

 the back side at the distal end. The length is 86 mm and the 

 diameter, just distalwards from the fourth trochanter, is 6"5" ,ln . 

 The fourth trochanter (tig. 1, T.) is 18 mm long and about 2 mni 

 high and is situated just beyond the middle of the shaft, 

 toward the distal end. 



Only the proximal end of the right tibia (fig. 1, R. T.) is 

 exposed and there the bone is well rounded. This, however, 

 may be only a small part of the proximal end, as the bone is 

 embedded in the rock. The left tibia (fig. 1, L. T.) is split 

 lengthwise, part of the bone lying in each half of the bowlder. 

 It is an almost straight, narrow shaft with the surface lying 

 uppermost bent slightly at the proximal end, due, probably, to 

 the expansion of the bone. In the position in which it lies, 

 the bone is of nearly the same diameter throughout, about 7 mni . 

 Its length is 104"'™. Lying close against the tibia and of 

 almost equal length is the extremely thin fibula (fig. 1, L. Fib.). 



There is a small, convex bone, i ram by 6 mm , lying where the 



* The first four text-figures have been drawn by Miss Clara Gould Mark 

 of Mount Holyoke College. For the privilege of using the restorations of 

 Professor Marsh I am indebted to the editor of this Journal. The photo- 

 graphs were taken by Mr. Asa S. Kinney of Mount Holyoke College. 



