191(5] 



Miller: Revieiv of Pavo Californicus 



91 



The stoutness of the shaft is remarkably constant for a praecocial 

 bird of the size of Pavo. The extremes of transverse diameter in birds 

 old enough to bear the spur are only 0.7 mm. apart. 



One of the characters by which Pavo is set off from Meleagris is 

 the presence of an incipient third ridge between the inner and the 

 outer ridges of the hypotarsus. This ridge is almost entirely wanting 

 even in old specimens of Meleagris gallopavo but is present in Pavo 

 californicus before the ossification of the plantar tendons, and is 

 equally marked in both sexes. This incipient ridge is but faintly 

 indicated in ill. ocellatus in both sexes, although both specimens at 

 hand are fully adult. "With respect to this character, the four species 

 under consideration fall into the following progressive series : M. gallo- 

 pavo, M. ocellatus, P. cristatus, and P. californicus. The outer ridge of 

 the hypotarsus is short and is dropped downward in Meleagris, is longer 

 and less prominent in Pavo cristatus, is longest and most prominent in 

 P. californicus. In the development of the spur and in the shape of 

 the spur core, P. californicus resembles Meleagris ocellatus more than 

 it does Pavo cristatus. In the elevation of the toes, the fossil form is 

 more like M. ocellatus than like P. cristatus. In elevation of the spur 

 it is almost identical with P. cristatus and far removed from M. 

 ocellatus. 



From the study of this bone only, the fossil species would seem 

 as far removed from either living species as the two living species are 

 from each other. 



In the original description of Pavo californicus, the statement was 

 made that the sexes were alike except for the presence or absence of 

 the spur core. This statement was based upon the erroneous con- 

 clusion that the fossil species followed Meleagris gallopavo in develop- 

 ing the spur as early as the ossification of the plantar tendons. A 

 young male specimen with the plantar ridge present but with the spur 

 lacking was identified as an adult female. With the present series 

 before one the error of this conclusion is easily noted. 



Tibiotarsus. — It will be seen from the above study of the tarso- 

 metatarsus in the Recent Pavo and the ocellated turkey that, Avhile 

 the bones in the two species are almost identical in length, the shaft 

 of the bone is appreciably heavier in Pavo. The exact reverse is found 

 to be true in comparing the tibiotarsi of the same two individuals. 

 The total length of this segment in the peacock is 197.7 mm., in the 

 ocellated turkey it is 187. The transverse diameter of the shaft is 

 8.5 mm. in the former and 9 mm. in the latter. 



