Scaphiopus holbrookii loi 



and they skim around the aquarium with the greatest rapidity. The tadpole 

 is of good size before the hind legs develop, and the back and abdomen 

 gleam with gold; the latter is dark gray, the former brown, with dark marks 

 on it showing the outline of the star of the adult starting from a broad dark 

 disk between the eyes. 



"As soon as the hind legs are out, both body and tail diminish, and they 

 are as ravenous as other tadpoles, devouring both meat and fish greedily. 

 As soon as the thread-like front legs show, they must have cork or clips to 

 sit on, as their perfection is close at hand. I neglected this at first, and some 

 that were ready to leave the water August i8, actually atrophied till they 

 were barely an inch long from snout to hind toe, the smallest live reptiles I 

 ever saw, and died evidently from inability to remain in their watery home. 

 It was only by giving them resting places, and a way out into a dry house, 

 that I succeeded in bringing out strong young ones, and the first act of their 

 terrestrial life seems to be to provide a home by burrowing. 



"When the front legs are well out in the toad, the whole under part 

 assumes a yellowish- white hue, the thighs are finely granulated, and on the 

 insides of the hands and feet the joints are thick and white. From between 

 the eyes and all over the back are the outlines of the future warts, increasing 

 in size daily. When the Spadefoot is at the same stage of growth the whole 

 underneath is dusky gray; feet and hands are slighter and smoother; the body 

 more drawn in behind the arms, and the tail is narrower." 



In 1923 (p. 406) we held "Scaphiopus holbrookii has bronzy tadpoles, 

 translucent crests, rounded tail tip, oblique black bars on musculature; labial 

 teeth 4/5." 



LARVAL PERIOD 



Nichols (1852, pp. 115, 116) gives the first account of this phase: "In ex- 

 amining the water, however, we found it filled with spawn — and two females 

 were drawn from the bottom of the pool. . . . 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 later became 

 perfect animals in less than four weeks. On the other hand, those kept in 

 water, without any opportunity to crawl on land, or on any substitute for it, 

 such as floating chip, or some foothold firmer than water, were slower in their 

 development. It seems then, that the development and successive changes 

 of the organs, confirm to circumstances. So long as water is wholly their 

 residence, their caudal appendage is necessary and accordingly used, retain- 

 ing its proportionate size and strength, and the growth of the legs is in the 

 same proportion. If the water be gradually withdrawn, and mud, moist 

 earth and then dry, gradually substituted, they will much sooner undergo 

 the change from the embryonic 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 con- 

 sistency of clay-mortar alone remaining. Here the young frogs were merrily 



