44 Sterile and Hjihvid Pheasants 



feathers, though in three cases both primaries and secondaries show a 

 slight tendency towards the male pattern. The breast feathers are 

 intermediate in colour between the cock and hen, being of a rufous 

 brown colour with some black patches, and occasional feathers showing 

 the purple and green lustre characteristic of the cock. The tail is of 

 the female type as a whole, but the black bars on the feathers tend to 

 be nari'ovver as in the cock. 



A partial a.ssumption of cock's plumage by female pheasants, as 

 above described, appears to be of fairly common occurrence, and it is 

 invariably associated, as far as the evidence goes, with some abnormality 

 of the ovar^'. Examples of the converse event, namely, the assumption 

 of hen's plumage by the cock, is far rarer, though a few cases have been 

 recorded (Hammond Smith, The Field, Feb. 25th, 1911, p. 384), and in 

 these cases the testes of the male show no abnormality or signs of 

 degeneration. In reply to enquiries Mr Hammond Smith writes to 

 me — "My experience is that female birds frequently assume male 

 characters as to plumage, and that this change is as a rule associated 

 with atrophy of the ovary which is often represented by merely a small 

 patch of black pigment. But I have never seen any trace of male 

 internal organs in these birds. This is a very common thing to see, 

 viz., the female assuming the male secondary sexual character. I have 

 seen it in fowls, ducks, grouse and pheasants. My special interest is 

 and has been for years to obtain specimens of the opposite change, 

 namely cocks assuming female characters. This is far more rare, in 

 fact I can only find three instances, one in the Ibis, 1897, one in Tring 

 Mu.seum, and the partial change mentioned in Shattock and Selig- 

 mann's paper {Trans. Path. Soc. London, Vol. Lvn. 1906). For eight 

 years I have looked for such a bird, and my friends have also done the 

 same; this winter I have got three specimens. Curiously although in 

 cases of female allopterotism the ovary is abnormal, in these cases of 

 male allopterotism the testes appear to be normal ; in each of my three 

 cases the testes have been carefully examined by S. G. Shattock of the 

 College of Surgeons." 



A. Bi'andt (6), writing in 1889, refers to " Arrhenoidie," or the 

 assumption of male plumage by the female, as a common occurrence in 

 various birds, and cites instances among Gallinacei, Passeres, Scansores, 

 Grallatores and Natatores. He remarks also that these cases are 

 always accompanied by ovarian abnormality. The opposite phenomenon, 

 " Thelyidie, " or the assumption of female plumage by the male, is, ac- 

 cording to Brandt, much rarer, but he is not so clear in regard to these 



