EMBRYOLOGY OF CRYPTOBRANCHUS 79 



no spermatozoa. He concludes that the presence of spermato- 

 zoa is not essentia] to the formation of the mass, but that they may 

 merely form an element of it; hence that the name 'Samenhaufen' 

 is scarcely justified. This conclusion is in essential agreement 

 with my results on C. allegheniensis ; it seems therefore that the 

 masses called 'Samenhaufen' in C. japonicus by Ishikawa are of 

 the same nature as the 'opaque bodies' of C. allegheniensis, and 

 like them of no significance in fertilization. The opaque body 

 apparently consists of coelomic fluid that has escaped into the 

 oviduct. 



The egg strings of Cryptobranchus japonicus as described by 

 Ishikawa ('04) and deBussy ('04) closely resemble in structure 

 those of C. allegheniensis. Both eggs and capsules of the Japan- 

 ese form are slightly larger; according to Ishikawa the egg proper 

 is about 7 mm. in diameter, and the capsule varies from 20 to 25 

 mm. in diameter in different spawnings. 



The egg capsules of Amphiuma as described by Hay ('88 and 

 '90) have the same general structure as those of Cryptobranchus. 

 For an opportunity to examine one of Hay's specimens of the 

 embryological material of Amphiuma, I am indebted to Prof. 

 C. W. Hargitt, to whom the specimen had been presented by the 

 finder. The egg capsule has a glistening surface like isinglass; 

 it is thinner and apparently tougher, and the connecting cord 

 more slender, than in Cryptobranchus. These peculiarities may 

 be due in part to preservation in alcohol, which tends to produce 

 the same condition in the envelopes of Cryptobranchus; but my 

 impression is that the egg capsules of Amphiuma are better 

 adapted to retain moisture when exposed to the air. 



Other amphibians whose egg capsules are fastened together 

 like a string of beads are Alytes, Ichthyophis, and Hypogeophis 

 (Brauer '97). 



The general appearance of the egg capsules of Necturus is 

 shown in figs. 55 and 56; some further details of structure are 

 shown in fig. 4. There are three layers to the gelatinous envelope : 

 (a) a comparatively thin but very dense inner layer, consisting 

 of several lamellae; (b) a thicker median layer of moderate density, 

 consisting of many lamellae; and (c) a very thick outer layer of 



