384 REPORT OF NATIONAL MUSEUM, 1893. 



How hard it is to overcome a popular error which has once taken 

 hold of the public mind is strikingly exemplified in the matter of the 

 growth of the rattle. It was obsfrved long ago, and commented upon 

 by competent observers and scientists, that the common belief that each 

 ring on a Eattlesnake's rattle represents a year of its life, and that its 

 age consequently can be ascertained by simply counting the number of 

 rings, is entirely erroneous. Still, the belief is so common that every 

 scientific writer who treats of Kattlesnakes finds it necessary to reiDeat 

 the (in print) threadbare denunciation of this fallacy, but evidently 

 without the slightest effect so far as the general public is concerned, 

 for the next newspaper report of the latest Ivattlesnake killed in the 

 neighborhood, and the newest edition of certain "popular" natural 

 histories, repeat the same old fallacy. I do not expect to have better 

 success than my jiredecessors in this respect, though it would not seem 

 to be difficult to make people understand that the rattle is a delicate 

 instrument which easily breaks; that old and huge Rattlers are often 

 found with but one or a few rings; that a variable number of joints are 

 added each year; and that the production of a ring can be accomplished 

 in the course of every two or three months. 



On the other hand, it is often asserted by good scientific authorities 

 that a new joint is formed at each general sloughing of the skin. 

 Schlegel* seems to have been the first to suggest this idea, which has 

 been indorsed, among others, by Garman, who says {op. cit, p. 259) that 

 the Rattlesnakes differ from other snakes " in retaining a portion of 

 each slough, that covering the tip of the tail, to form one of the rings 

 of the rattle." 



It has already been shown that the formation of the rings, or but- 

 tons, is a process of sloughing analogous to, or rather identical with, 

 that of the rest of the outer skin, but this does not necessarily imply 

 that the sloughing takes place at the same time, or that a new button is 

 formed every time a sloughing of the skin takes place. Recent obser- 

 vations by a prominent Russian investigator. Dr. A. E. Feoktistow, 

 seem to indicate that the two processes are, to some extent at least, 

 independent. His conclusions are sufficiently important to warrant 

 the following quotations from his paper: t 



In June, 1887, 1 received ten living specimens of Crotalus durissus, which I have 

 since been able to observe closely. Owing to wiint of a sufficient quantity of suita- 

 ble food (the animals refused to eat anything but very young rabbits), I lost five of 

 them in the course of the first six mouths. The remainder are in good condition, 

 and now (August 16, 1888) devour birds in addition to rabluts. They live in a large 

 terrarium provided with a spacious water reservoir, cement fioor, and a permanent 

 hot-water heating apparatus which renders it possible to maintain the temperature 

 of the air in the interior at 20= to 22-^ R (=77° to 81.5- F). The snakes are provided 

 with living food in sufficient abundance, and are equally lively in winter and summer. 



*Essai sur la physiouomie des serpens, 1837. ii, p. 5.57. 



t Zur Physiologie der Klapper des Crotalus durissus. Bull. Acad. .Sc. St. Peters- 

 bourg (n. s.) i, 1889, pp. 1-4. Also in Mt51. Biol. Acad. Sc. St. Petersb., xii, livr. 1, 

 1891, pp, 1-4. Translated in Ann. Mag. Nat. Hist. (6) xi, Jan., 1893, pp. 54-58. 



