ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
273 
Section through a testicular fragment, showing enormous hyper- 
trophy of interstitial cells, and the seminiferous tubules with only 
one stratum of cells. 
clearly show ; it lias nothing to do with the internally secretory function 
of the testicle in its relation to the organism as a whole ; it is caused by 
local conditions. J. A. T. 
Duck Hybrids. — A. Lecaillon ( Comptes Rendus Acad. Sci ., 1922, 
174, 1431-3). Record of a male hybrid between Dafila acuta { male) 
and Anas hoschas (female). This male hybrid had offspring by a 
female wild duck. The offspring produced fertile eggs. J. A. T. 
Inadequate Egg-shells in Pigeons.— Oscar Riddle ( Amer . Journ. 
Physiol ., 1921, 57, 250-63). Individual female pigeons which occa- 
sionally produce soft-shelled eggs, and obviously thin-shelled eggs, may 
produce other eggs with normal or extra-thick shells. A very high 
proportion of the embryos which arise in all these groups of eggs die 
before hatching. The production of inadequate shells and the early 
tissue, the number and size of the interstitial cells being very markedly 
augmented. The hypertrophy is not compensatory, as experiments 
