292 Zoological Proceedings of Societies. 



change of plumage. The ovarium Mas shrunk, purple, and hard J 

 the oviduct diseased, and the canal obliterated at the upper part, 

 immediately preceding its funnel-shaped enlargement at the 

 bottom of the ovarium. Having opened a Ilen-Pheasant in her 

 natural plumage, for the sake of comparison, he found a similar 

 diseased state of the organs to exist ; thus proving that the dis- 

 ease must exist some time before the corresponding change of 

 feather takes place. He observes, that it is no uncommon thing 

 to find among numerous broods of pheasants reared by hand, 

 some females, Avhich, at the age of only four months, produce 

 the brightest plumage of the male : and in two instances of birds 

 shot in a wild state, the nest-feathers had not been shed, proving 

 them ta have been birds of the year. 



A Partridge, having a white bar across the breast, and the 

 first three primaries in each wing white, being opened, exhibited 

 the same sort of organic disease ; and, from circumstances ad- 

 duced, it appears that this was also a bird of the year. 



But all variations in plumage are not traceable to this cause. 

 In most of the excepted instances, however, the individuals are 

 dwarf birds; and the authour attributes their variety of plumage 

 to defective secretion — the effect of weakness. 



When the sexual organs are artificially obliterated in the com- 

 mon fowl, so soon as the operation is performed in the male 

 bird, he ceases to crow, the comb and gills do not attain their 

 full size, the spurs remain short and blunt, and the feathers of 

 the neck assume an appearance intermediate between the hackled 

 character of the cock and the ordinary web of the hen. When 

 the oviduct of the female is obliterated, the ova cease to enlarge ; 

 she makes an imperfect attempt to crow ; the comb increases in 

 size, and short and blunt spurs make their appearance. The 

 plumage alters in colour and in form, approaching to that of the 

 cock ; the bones of the lower part of the back also never acquiring 

 the enlargement requisite for giving a proper breadth to the 

 pelvis. In short, the two sexes approximate so nearly in charac- 

 ter by this process, that it frequently becomes difficult to deter- 

 mine the sex. 



Hen-Pheasants assume tlit- plumage of the male at best but 



