AND OF HYBRID PIGEONS. 
43 
degeneration was more marked. This might be due to the 
fact that the bird was older than the first. 
III. Age, 13 months. Parentage: male, a hybrid from a 
white and brown ring dove; female, homer. The testes were 
very small. The vas deferens and genital papillae were normal. 
In the testes degeneration was extreme. Many of the tubules 
had lost nearly all of their germ cells. Numerous leucocytes 
were present. In some of the less affected tubules an occa¬ 
sional spermatid had become partially transformed into a sper¬ 
matozoon, though no adult spermatozoa were found. In some 
tubules stroma-like cells were present. 
IV. Age, 11 months. Parentage: male, wild passenger 
pigeon; female, brown ring dove. The testes were of medium 
size. Inspection showed about the same conditions as existed 
in Hybrid III, although hardly as extreme. 
V. Age, 23 months. Parentage: male, wild passenger 
pigeon; female, brown ring dove. This bird was thought to be 
a female up to the time it was killed. It was mated with two 
different males and always played the role of a female. The 
testes were found to be extremelv small. The vas deferens 
was poorly developed and tapered off to a fine thread at the 
cloaca. The genital papillae were rudimentary. The degree 
of degeneration which prevailed surpassed that found in any 
of the other males. In many tubules only the peripheral layer 
of spermatogonia persisted; some of these, however, still 
showed mitotic divisions. Other tubules had become almost 
completely replaced by connective tissue. Not all tubules were 
equally affected. In some several layers of cells yet remained, 
but in dividing nearly every cell exhibited the spermatogonial 
type of chromosome and spindle. In a very few cases the 
regular spermatocytic type of chromosome was to be seen. 
VI. In connection with the male hybrids, it is perhaps well 
to mention another peculiar pigeon which was obtained from a 
dealer and whose antecedents are consequently unknown. It 
may have been a crossed form from two different varieties of 
dove-cot pigeons. The color markings were unusual. The 
neck and head showed numerous irregular splashes of white 
arranged in no definite pattern. There were extensive abnor- 
