No. 2.] EARLY DEVELOPMENT OF AMBLYSTOMA. 345 



The migration to the breeding grounds probably occurs at 

 night, since they are rarely seen on land during the day. Their 

 abrupt appearance in large numbers has often been noted, and 

 at this time they may be easily captured; their appearance is 

 no less sudden than their departure, — in two or three days 

 they become extremely scarce and soon disappear. 



They seem to be carnivorous ; dissections of the alimentary 

 tract indicate that their food is largely Crustacea. The young 

 eagerly devour pieces of meat or insect larvae. In the absence 

 of other food they prey upon each other. 



The female is very choice in selecting a place to deposit her 

 eggs, striving to obtain a position where she can rest upon a 

 small twig or blade of grass and at the same time keep her 

 nostrils above the water. She then clasps the twig between 

 her posterior limbs and presses it tightly against the cloaca. 

 The eggs escape singly, and adhere to the object on which they 

 are deposited. The process may be continuous, covering a 

 period of one or two hours, or at irregular intervals, lasting 

 from a few hours to a day. The eggs may be deposited singly 

 or in masses of a hundred or more. 



In some localities the water is so turbid that considerable 

 difficulty is experienced in obtaining the eggs. By placing 

 a number of bushes in the pond the animals were attracted ; 

 the following morning the bushes were raised and a part of 

 the eggs collected. In this way freshly deposited eggs were 

 readily obtained. 



The fresh eggs are so closely crowded together and firmly 

 held in place by the gelatinous envelopes that they can only 

 be removed with difficulty ; after remaining in the water for a 

 few hours the envelopes swell and the removal is easily effected. 

 At this time the ^gg presents the appearance indicated in 

 PL XVIII, Fig. I, being enclosed by three concentric envel- 

 opes. The outermost, by means of which the eggs become 

 attached to the object on which they are deposited, is trans- 

 parent and structureless. Numbers of minute algae are often 

 found in this membrane ; but their presence in the internal 

 envelope, as noted by Orr ('88), has not been observed. The 

 middle envelope presents a more irregular outline. When 



