8 INHERITANCE IN POULTRY. 



Standard of Perfection (1905, p. 13), which speaks of the hollow protruding 

 nostrils. Wright (1902, p. 441) in treating of the cranial dome says : 

 " Excess in one part being often connected with defect in some other, as 

 Mr. Darwin pointed out, the skulls with this peculiarity usually show a 

 chasm in the intermaxillary bones, which in other fowls support the roof of 

 the nostrils ; owing to which deficiency in bony support the nostrils of all 

 heavily crested fowls appear flattened and depressed and yet cavernous in 

 character." Darwin (1876, Chapter VII) attributes the width of the nostrils 

 to the circumstance that the branches of the premaxillary and of the inner 

 processes of the nasal bone are somewhat upturned. 



Comparing the skull of a Polish fowl with that of a Minorca, I find the 

 following relations : 



First, the nasal bone has in the Minorca as in most other fowl the form of 

 the Greek >■ ; the single stem (processus frontalis) projects caudad and lies 

 as a flat plate above the frontal bone by which, also, it is cut off from contact 

 with most of the lachrymal bone. The two anterior branches enclose between 

 them the olfactory space. The processus maxillaris runs nearly perpendic- 

 ular to the maxillary bone ; the processus premaxillaris is a slender stylet 

 terminating over the middle of the olfactory space and embracing the nasal 

 process of the premaxillary bone (Fig. A, 2, ?^). In the Polish fowl the pro- 

 cessus frontalis is relatively shorter and broader. The whole central nasal 

 area is greatly depressed, forming a cavity in front of the cranial dome — a 

 cavity that is filled with the cartilaginous foundation of the rudimentary 

 comb. In front of this depression of the skull the processus premaxillaris 

 rises, reaching about the normal height of this part of the nasal bone, and 

 stops there in the posterior quarter of the nasal space. Thus the bony 

 nasal space is posteriorly of normal height. What is peculiar in the skull 

 of the Polish fowl is that the processes premaxillaris are very short and slender 

 and do not embrace the nasal process of the premaxillary, but instead the 

 cartilaginous dorsal edge of the orbitosphenoid or mesethmoid. This thick- 

 ened dorsal edge continues anteriorly as the edge of the internasal septum, and 

 it replaces the nasal processes of the premaxillary. Anteriorly the septum 

 abuts upon the premaxillary. At this point there is adhering to the premax- 

 illary a mass of tissue in the median plane which seems to be the rudiment 

 of the nasal process of the premaxillary. 



In criticism of Darwin'sexplanationof the wide nostril based on the ground 

 that the nasal process is upturned, it may be said that the wide nostril lies in 

 front of the upturned nasal bone and in a part of the nasal space that is not 

 higher (nor wider) than in the normal skull. I think it must be concluded 

 that the wide nostril is independent of the width of the nasal space. As we 

 shall see later, the wide nostril is never found in connection with a single comb. 



3. Form of Skull. — Polish fowl have long been noted for the remarkable 

 form of their skull. This was referred to by Bovelli (1670, cent. 2, p. 157, 



