78 BERTRAM G. SMITH 



embryo that I have found in nature, for in this ease, to be 

 described later, each embryo is half the normal size. 



After fertilization, numerous spermatozoa are found imbedded 

 in the egg capsule, and floating in the liquid between the capsule 

 and the egg; they also occur in capsules that do not contain eggs. 

 The spermatozoa occur singly, not in masses, and they are entirely 

 absent from eggs taken from the uterus. Fertilization occurs 

 only after the eggs have been deposited in the water (Smith, '07). 



An envelope so tough and thick as that of Cryptobranchus 

 must exert a decided selective power with regard to the spermato- 

 zoa; of a considerable number of spermatozoa simultaneously 

 coming in contact with the envelope, the most vigorous, as well as 

 the ones structurally best adapted, would succeed in first entering 

 the egg. 



Floating in the liquid between each egg and its envelope, there 

 occurs a fairly large irregular and slightly opaque mass, in appear- 

 ance like a faint white cloud (see fig. 1 ; this mass is also faintly 

 shown in the photograph, fig. 54). Under the microscope it is 

 found to consist of a clear viscous matrix in which are imbedded 

 numerous leucocytes and occasionally a few erythrocytes. In 

 fertilized eggs, this mass, which I have called ('07) the 'opaque 

 body' sometimes contains spermatozoa, but they are not restricted 

 to it, nor especially numerous in it. The opaque body is uniformly 

 present in eggs that do not contain spermatozoa. 



A mass similar in general appearance and location to that de- 

 scribed above as the opaque body, is figured by Ishikawa ('04) 

 within the egg capsule of Cryptobranchus japonicus. In the text 

 he refers to these masses as 'Samenhaufen,' and speaks of the 

 presence of spermatozoa within the egg capsules as evidence of 

 internal fertilization. He considers it improbable that the sper- 

 matozoa are able to penetrate the egg capsule, and supposes that 

 they are taken up into the oviduct before the egg capsules are 

 formed. 



DeBussy ('04, p. 11) found a mass ('vlokje') of similar appear- 

 ance within the capsules of unfertilized eggs of C. japonicus. 

 Under the microscope he found the mass to consist of a slimy sub- 

 stance containing red blood corpuscles and yolk granules, but 



