Chap. VII. 



OSTEOLOGICAL DIFFERENCES. 



275 



branches of the premaxillary rest, is very little depressed. These 

 l^eculiarities no doubt stand in close relation with the broad, flattened 

 rose-comb characteristic of the Hamburgh breed. 



I have examined fourteen skulls of I'olish and other crested hreeds. 

 Their differences are extraordinary. Fu-st for nine skulls of dif- 

 ferent sub-breeds of English Polish fowls. The hemispherical pro- 

 tuberance of the frontal bones ''* may be seen in the accomiDanying 



I B 



Fig. 34.— Skulls of natural size, viewed from above, a little obliquely. 

 bankiva. B. White-crested Polish Cock. 



A. Wild Gallus 



drawings, in which (B) the skull of a white-crested Polish fowl is 

 shown obliquely from above, with the skuU (A) of O. bankiva in the 

 same position. In fig. 35 longitudinal sections are given of the 

 skull of a Polish fowl, and, for comparison, of a Cochin of the same 

 size. The protuberance in all Pohsh fowls occupies the same position 

 but diiiers much in size. In one of my nine specimens it was ex- 

 tremely slight. The degree to which the protuberance is ossified 

 varies gi-eatly, larger or smaller portions of bone being replaced liy 

 membrane. In one specimen there was only a single open pore ; 



^* See Mr. Tegetmeier's account, 

 with woodcuts, of the skull of Polish 

 fowls, in ' Proc. Zoolog. Soc.,' Nov. 

 2.5th, 1856. For ofher references, see 

 Isid. Geoflroy Saint- Hilaire, ' Hist. 

 Gen. des Anomalies,' torn. i. p. 287. 



M. C. Dareste stispects (' Recherches 

 sur les Conditions de la Vie,' &c,, 

 Lille, 1863, p. 36) that the protuber- 

 ance is not formed by the frontal 

 bones, but by the ossification of the 

 dura mater, 



T 2 



