288 FOWLS. Chap. VII. 



but little, and, out of twenty-five sternums examined by me, three 

 alone were perfectly symmetrical, ten were moderately crooked, and 

 twelve were deformed to an extreme degree. Mr. Eomanes, however, 

 believes that the malformation is due to fowls whilst young resting 

 their sternums on the sticks on which they roost. 



Finally, we may conclude with respect to the various breeds 

 of the fowl, that the main bones of the wing have probably 

 been shortened in a very slight degree ; that they have certainly 

 become lighter relatively to the leg-bones in all the breeds in 

 which these latter bones are not unnaturally short or deli- 

 cate ; and that the crest of the sternum, to which the pectoral 

 muscles are attached, has invariably become less prominent, 

 the whole sternum being also extremely liable to deformity. 

 These results we may attribute to the lessened use of the 

 wings. 



Correlation of Growth. — I will here sum up the few facts 

 which I have collected on this obscure, but important, subject. 

 In Cochin and Game fowls there is perhaps some relation 

 between the colour of the plumage and the darkness of the 

 esrar-shell. In Sultans the additional sickle-feathers in the 



CD O 



tail are apparently related to the general redundancy of the 

 plumage, as shown by the feathered legs, large crest, and 

 beard. In two tailless fowls which I examined the oil-gland 

 was aborted. A large crest of feathers, as Mr. Tegetmeier 

 has remarked, seems always accompanied ~by a great dimi- 

 nution or almost entire absence of the comb. A large beard 

 is similarly accompanied by diminished or absent wattles. 

 These latter cases apparently come under the law of com- 

 pensation or balancement of growth. A large beard beneath 

 the lower jaw and a large top-knot on the skull often go 

 together. The comb when of any peculiar shape, as with 

 Horned, Spanish, and Hamburgh fowls, affects in a corre- 

 sponding manner the underlying skull ; and we have seen 

 how wonderfully this is the case with Crested fowls when 

 the crest is largely developed. With the protuberance of the 

 frontal bones the shape of the internal surface of the skull 

 and of the brain is greatly modified. The presence of a crest 

 influences in some unknown way the development of the 

 ascending branches of the premaxillary bone, and of the 



