STUDIES IN THE EXPERIMENTAL ANALYSIS OF SEX. 159 
Studies in the Experimental Analysis of Sex. 
Part 9. — On Spermatogenesis and the Formation of Giant 
Spermatozoa in Hybrid Pigeons. 
By 
CjicoAi'tw Smith, M.A., 
Fellow of New College, Oxford. 
With Plate 8. 
The cytological investigation which forms the subject of 
this study is based on the examination of the testes of three 
male hybrids, which resulted from the crossing of a female 
domestic dove with a male magpie pigeon. The three birds 
which were the sole progeny of this mating were all males, 
and I may mention here that the only other hybrid bird I 
have succeeded in obtaining was also a male, the cross in this 
case being between a male bantam and a female pheasant. 
Of about sixty eggs incubated from- this latter cross only one 
chick was obtained, which suffered from a cerebral heruhi 
and died two days after hatching. The testes of this 
liybrid were perfectly normal, and microscopical investigation 
showed they wei’e in the same state of development a.s in an 
ordinary chick of the same age. The fact that all the four 
hybrid birds dealt with by me were males is in complete 
agreement with Guyer’s records, which show a/U enormous 
preponderance of males over females in hybrid pigeons and 
gallinaceous birds (1). 
Two of the three hybrid pigeons (A and B) which furnished 
