70 MR. T. E. GUNN ON THE 



Some very excellent notes on the subject by Signora C. Picchi 

 appear in the July (1911) number of ' British Birds,' pp. 45-49. 



This lady gives 27 examples of a persistent right ovary, the 

 large majority of them (25 out of 27) are found among the 

 Falconida?, especially the genera Falco and Circus. 



For the purposes of this paper I have reduced Signora C. Picchi's 

 notes to a tabulated foim (Table II., p. 73) in order to render it 

 readily comparable with the table (Table I.) constructed from my 

 own series. 



Ornithologists expect to find either two testes or one ovary. The 

 intestines and peritoneal folds are raised and gently turned over 

 from the (bird's) left to right, which of course exposes the left half 

 of the dorsal wall of the body-c;i,vity. In the case of the female 

 the left ovary is satisfactorily identified, and there the dissection 

 usually stops. 



The conditions obtaining on the right side of the body-cavity 

 are not investigated at all, — a second ovary may or may not be 

 present, but by this method of examination it is eftectually hidden 

 by the pile of intestines pushed over from the left side. 



The percentage of double ovaries foinid in this paper in certain 

 genera in the family (Circuf! 9 out of 12, Accipiier 14 out of 20) 

 is so large that one is forced to the conclusion that individuals 

 of the same genera dying in captivity would also furnish a 

 cousiderable percentage of paired ovaiies. 



In the 45 instances of double ovaries referied to (Table I., 

 group 1) nearly three quarters (33 out of 45) are of one family, 

 the Falconidaj. 



In Signora C. Picchi's notes (Table II., group 1) 27 examples 

 are given, and of these 25 are draAvn fi'om the same source. 



The remaining twelve examples in my series (Table I., group 2) 

 represent seven species that, with the exception of the two Grouse, 

 ai'o widely separated. The seven species in fact belong to six 

 diiferent ordeis. 



The remaining two in Signora C. Picchi's notes (Table I., 

 gi'oup 2) also occur in two very divei'se species, one of them being 

 an Owl [jSiriges) and the other a Rook (Corrus). 



Oddly enough, I have no note of paii'ed ovaries among the 

 Strigida^ ; but that may be due to so few of these birds passing 

 through my hands in recent years, owing to the wise protection 

 which is now almost universallv nfibrded owls in this countiy. 



Tal)le I. (T. E. G.) and Table II. (C. Picchi) show clearly 

 enough that the right ovary does pei'sist in not a few cases ; that 

 it is sometimes developed equally with the left and sometimes very 

 considerably exceeds that gland. 



P {Circus cineraceiis), in which the right ovary has several large 

 ripe ova whereas those of the left are small. 



8" (Accipiter uisus). The right ovary is but fragmentary, and 

 shows only three ova. : one as lai-ge as an oi'dinary sized marble, 

 another about one third that size, and the third about as large as 

 a, heuipseed. Tlmse of the left were quite small. The right 

 ovary had evidently been the soui'ce fi'om whieli the season's eggs 



