Nichols on Scaphiopus Solitarius. 115 



appearance, with a pair of the frogs, were forwarded tome 

 by Mr. Amos Swinerton. In the afternoon of the same day, 

 I repaired to the spot, accompanied by several members of 

 the Essex County Natural History Society ; but the sun had 

 appeared meanwhile, their voices were hushed, and none 

 were even to be seen. In examining the water, however, 

 we found it filled with spawn and two females were 

 drawn from the bottom of the pool. In the evening follow- 

 ing they came out again ; resumed their croaking and ama- 

 tory habits. Several more specimens were captured and 

 kindly presented to us, by Mr. Nathl. Pope, whose name 

 has been already mentioned. The old frogs were not seen 

 again. In five days after, I found the spawn had become 

 tadpoles, of which about a hundred I took home kept 

 them in glass globes, fed them on fish and flesh scarcely 

 one died. They remained longer and grew larger in the 

 tadpole state than did those left in their native pool, which 

 latter became perfect animals in less than four weeks. On 

 the other hand, those kept in water, without any opportu- 

 nity to crawl on land, or on any substitute for it, such as a 

 floating chip, or some foothold firmer than water, were 

 slower in their development. It seems then, that the de- 

 velopment and successive changes of the organs, conform 

 to circumstances. So long as water is wholly their resi- 

 dence, their caudal appendage is necessary and according- 

 ly used, retaining its proportionate size and strength, and 

 the growth of the legs is in the same proportion. If the wa- 

 ter be gradually withdrawn, and mud, moist earth and then 

 dry, gradually substituted, they will much sooner undergo 

 the change from the embryotic to the infantile condition of 

 existence. Thus, at the end of four weeks, all the water 

 in which the spawn was deposited had evaporated ; in some 

 of the lowest spots of the basin a little mud of the consist- 

 ence of clay-mortar alone remaining. Here the young frogs 

 were merrily hopping about, enjoying life on dry land, 

 while those in confinement in water, were still increasing 

 in size, and yet in an embryo condition. This very short 

 natural period of the tadpole state admirably fits them for 



