242 



SCIENCE. 



[N. S. Vol. XVII. No. 424. 



Tadpoles of the Green Tree Toad {Hyla 

 versicolor) and Comparison with the 

 Common Toad {Bufo lentiginosus) : 

 Simon H. Gage, Cornell University. 

 The most obviouSj although by no means 

 the most important, change in transforma- 

 tion is the disappearance of the tail. Com- 

 paring the common and the tree toad, it 

 was found that in the tadpoles of the com- 

 mon toad the tail shortened 4.6 mm. in 

 24 hours, while that of the tree toad short- 

 ened 24 mm. in 24 hours, or more than 

 five times as rapidly as the common toad. 

 Although the common toad is considerably 

 larger than the tree toad, the tadpoles of 

 the latter are much the larger— that is, 

 from two to three times the length from 

 tip to tip. If one compares the percent- 

 age of the total length which disappears 

 in the two cases, it is found that in Bufo 

 the diminution is 25.5 per cent., while in 

 Hyla it is 47 per cent, in 24 hours. That 

 is, the relative as well as the absolute 

 amount of shortening is greater in the tree 

 toad in a given time. 



In coloration the common toad tadpoles 

 are entirely black or barred. The small 

 tadpoles of Hyla are less deeply pig- 

 mented, but of nearly a uniform shade. 

 As the tadpoles approach their greatest 

 perfection as tadpoles, the coloration as- 

 sumes a brilliant red, mottled with black. 

 This makes them very conspicuous. The 

 appearance is especially striking when the 

 sunshine is strong. When transformation 

 approaches, the green color so character- 

 istic of younger tree toads appears on the 

 body, and the red may become less brilliant 

 in the tail, but often that remains and the 

 animal is brilliant in red and green. 



Every effort to get at the meaning of 

 this coloration in the tadpoles was unsuc- 

 cessful. It can not be for attraction, as 

 the animals are immature. It can not be 

 for protection, as there are no similarly 

 colored objects in the water. It can not 



be a warning color, as the animals are 

 readily eaten by animals living more or 

 less on tadpoles. 



The Habits of Cryptoiranchus: Albert 

 M. Reese, Syracuse University, Syra- 

 cuse, N. Y. 



Cryptobranchus alleghaniensis, or hell- 

 bender, occurs in great numbers in streams 

 of the Ohio valley, but is apparently sel- 

 dom found outside of that region. It 

 sometimes reaches a length of 60 cm., and 

 though it is a repulsive looking animal, 

 and has the reputation among fishermen 

 of being poisonous, it is really a most 

 harmless and inoffensive creature. 



Respiration in the adult is by means of 

 well-developed lungs, but there is a per- 

 sistent gill-opening on each side of the 

 throat. Air for respiration is taken in 

 by a curious swallowing motion, and is 

 exhaled partly by a quick expiration, when 

 the animal comes to the surface to breathe, 

 and partly by bubbles set free as the ani- 

 mal lies on the bottom. In captivity, the 

 respiration intervals seem to be quite vari- 

 able, the average length of time between 

 inspirations being about 15 minutes, the 

 longest recorded interval being 43 minutes. 

 Under natural conditions, the hellbender 

 seems to be a remarkably voracious animal, 

 living chiefly on small fish, crayfish, etc., 

 but in captivity its appetite is quite mod- 

 erate, a few small pieces of raw liver once 

 or twice a week being all that it wiU eat in 

 the summer, while in the autumn several 

 specimens kept under observation in a tank 

 refused to eat during a period of over two 

 months. One morning at the end of this 

 long voluntary fast, a black object was 

 seen projecting from the mouth of a large 

 hellbender which, on closer examination, 

 proved to be the tip of the tail of a smaller 

 individual which had been swallowed head 

 first. By means of forceps the small hell- 

 bender was rescued from his strange pre- 



