Vol. 5] 



Miller. — Pavo Calif or ulcus. 



287 



is thirty-five per cent, of the total length in the type of P. cali- 

 fornicus as against twenty-eight per cent, in P. muticus and 

 thirty per cent, in P. cri status. The two fragments (165/1 and 

 no. 11299) show absolute dimensions which correspond very close- 

 ly to those of the type specimen in this regard, and suggest a 

 similar ratio if the total length were obtainable. 



The angle formed by the intersection of the long diameter 

 of the shank and the axis of the spur is a constant quantity in 

 four specimens of P. calif ornicus at hand. This angle on the 

 proximal side of the spur is less than a right angle and decidedly 

 more acute than in P. muticus. 



The spur core in P. calif amicus is markedly less robust than 

 in P. muticus. The actual length in the type is only slightly 

 less than in that species, yet it is only about three-fourths as 

 broad. In the fragmentary specimens the tip of the spur is 

 wanting, but the angle included between the upper and lower 

 margins indicates similarity to the type. In fact, the four speci- 

 mens bearing the spur show a surprising degree of uniformity 

 throughout in the development and position of this somewhat 

 superficial structure. 



The distal end of the shank shows a distinctive character in 

 the place relation of the three troehleae.- The degree of eleva- 

 tion of the lateral toes above the plane of the middle toe is rela- 

 tively greater in P. calif ornicus than in P. muticus. The eleva- 

 tion in proportion to the total length of the shank is forty per 

 cent, against twenty-nine per cent, for the outer toe, and fifty- 

 four per cent, against forty-three per cent, for the inner. The 

 distal fragment (no. 11299) shows absolute measurements uni- 

 form with the type. 



The plantar ridge extending from the hypotarsal prominence 

 to the base of the spur core is a character readily distinguishing 

 Pavo from Gallus and Phasianus. In the type of P. calif ornicus 

 this ridge is perforated at its proximal end by a large opening 

 through which the adductor tendon to the outer toe doubtless 

 passed. In Milne-Edwards' figure of P. muticus, this opening 

 has a length of 20 mm. The character of this ridge suggests 

 the probability of its being exceedingly variable, and that the 

 extent of ossification is dependent on age. The three specimens 



