COPEIA 19 



(Crotalus horridus) from the neighborhood which he 

 kept in a glass case, and maintained a summer tem- 

 perature the year round, with the result that during 

 that period of three years the snakes did not hiber- 

 nate, but maintained an active existence during the 

 entire time. He has observed that they have shed 

 their epidermis at shorter periods than has been gen- 

 erally supposed; to wit, about once in three months, 

 and that this is not a constant factor, but will vary. 

 It has popularly been held as an indisputable fact 

 that the rattle-snake adds one joint to the rattle 

 each year, but Mr. Ford has discovered that a new 

 joint is added to the rattle with each shedding of the 

 eperdermis, and the snakes in his collection have add- 

 ed from three to four buttons each year, proving that 

 the old time hypothesis is erroneous. The snakes have 

 hue rattles with perhaps ten or twelve buttons and 

 have attained a length of maybe less than twenty 

 inches. In this collection, under the scrutiny of Mr. 

 Ford, is a small mud turtle (species unknown) that 

 is kept at about the same temperature as the snakes 

 but with different results. As winter approaches and 

 the proper season arrives it declines to eat, draws in 

 its head and becomes lethargic and finally falls into 

 a stupor, which lasts till spring when it awakes again 

 to its wonted life and activity. From these facts, it 

 would be interesting to determine what degree of cold 

 a dormant animal may be subjected to without de- 

 stroying its latent vitality, and what degree of tem- 

 perature is necessary to induce hibernation in any 

 given animal. 



Herman Haupt, Jr., 



South Haven, Michigan. 



ON ONE OR TWO COMMON STRUCTURAL 



ADAPTATIONS IN FISHES. 



The caudal fin of fishes is the chief propelling 

 organ. As such its form is a good criterion of a fish's 



