EMBRYOLOGY OF CRYPTOBRANCHUS 



75 



The egg proper is perfectly spherical when fresh, but it gradu- 

 ally becomes slightly oblate from the effects of gravity. It is 

 about the size of a pea, and bright yellow in color — a rather deep 

 yellow at the lower pole, grading to a very pale yellow at the upper. 

 The general intensity of the yellow color varies considerably 

 in eggs of different spawnings, but is quite uniform in eggs from 

 the same female. The absence of black pigment is probably 

 correlated with the fact that the eggs are laid in darkness: the 



Fig. 1 Eggs and egg envelopes of Cryptobranchus allegheniensis, natural size. 

 op. h., opaque body; lam. z., lamellar zone of envelope. 



! Fig. 2 Optical longitudinal section through the lamellar zone of the envelope 

 in the region of junction of the egg capsule with the connecting cord. X 13. 



Fig. 3 Spermatozoon. X 500. vi., middle piece. 



