288 



University of California Publications. 



[Geology 



at hand show this variability, and if the extent of ossification 

 be indicative of age, the type specimen must represent an indi- 

 vidual of complete maturity. This opening' in the type of P. 

 calif ornicus measures only 8 mm. At a distance of 8 mm. from 

 the lover margin of the opening there appears a minute per- 

 foration of the ridge, which probably marks the point to which 

 the opening extended in the earlier adult life of the individual. 

 In the two fragments showing the distal end of the shank, the 

 dimensions of this opening are 18 mm. and 10 mm. Proximal 

 fragment no. 11297, though sufficiently long, shows no trace of 

 the spur core, and may reasonably be considered as from a female 

 individual. The dimensions obtained show size ecpial to that 

 of the type. Unfortunately, the free edge of the plantar ridge 

 is broken away, but sufficient remains to indicate a development 

 quite equal to that of the male, and an opening 18 mm. in length. 



We may conclude that the sexual differences in the tarsus 

 of P u calif ornicus are limited to the presence or absence of the 

 spur core. It is also probable that the type is from an adult 

 male and represents the species by a very constant group of 

 characters. 



Unfortunately, the only available material of P. cristatus 

 was a live bird. Very careful measiirements of the metatarsal 

 segment in an adult male showed the dimensions in the table 

 above. These are sufficiently different from those of P. calif or- 

 nicus to demonstrate the distinctness of the two species. 



Students of ornithology have in general laid minor stress 

 on palaeontological evidence in the determination of centers of 

 distribution. This fact is due in large measure to the scarcity 

 of fossil material representing existing groups. The encounter- 

 ing of the California peacock so far out of the previously known 

 range of the genus Pavo becomes, then, a matter of interest in 

 this connection. The present range of the subfamily in which 

 the peacock is placed is exceedingly limited compared with its 

 former distribution. Phasianine forms are now limited to the 

 Indian Eegion ; but fossil forms are recorded from the Miocene, 

 Pliocene, and Quaternary of Europe, and from the Siwalik beds 

 of India. The occurrence in Europe seems to be in decreasing 

 numbers. Our record is exceedingly imperfect, but with the 



