Say on Htrpetology, 257 



V. Latr. Lacep. Shaw, Daudin, &c. Jlgkistrodon mokasen of 

 Beauvois ; which opinion is not a little corroborated by an 

 actual comparison of one of these animals in Peaie's Museum, 

 with the descriptions of the authors above mentioned. It 

 may be objected to me, that the mockeson of those naturalists 

 is a Cenchris, and not a Scytale, therefore generically distin- 

 guished from the Copper-head ; but on the other hand, we 

 know that the genus Cenchris does not exist in nature, that the 

 individual upon which it was founded, was either a fortuitous 

 variety, or that the illustrious naturalist was deceived by the 

 desiccation of his specimen, giving to the basal caudal plates a 

 bifid aspect. That the former was the case I analogically 

 infer, from having seen, in the collection of the Academy of 

 Natural Sciences, a Coluber heterodon, of which the fifth and 

 sixth pairs of caudal scales were entire, and not as usual bifid. 

 An additional corroboration of the truth of this inference is 

 derived from the circumstance of the Scytale of Peaie's Mu- 

 seum, having the ten or eleven apicial caudal plates bifid, 

 precisely as in the genus Acanthophis, to which it seems 

 closely affianced, and to which it would be referred if this 

 character was a permanent one. In every other character 

 this specimen coincides with the S. mockeson of authors, and 

 in every necessary respect with the S. cupreus of Mr. R. with 

 the sole exception of the calcarate termination of the tail. 

 This caudal horn seems to approximate Mr. R's. animal to the 

 S. piscivorus or true horn-snake, about which the credulous 

 have so absurdly alarmed themselves, and which was arranged 

 with the Crotali by Lacepede, in consequence of having a horn 

 on the tail an inch long. We find sometimes a small indurated 

 tip to the tail of Coluber melanoleucns* at least upon some full 

 grown specimens, formed by the elongation and appression of 

 the terminal scales ; a larger one on that of the European 

 viper, and of the Acanthophis cerastes, and Brownii. Mr. 

 Peaie's specimen certainly has not the horn, but it has at the 



* This large species I understand has been mistaken by a writer on Natural 

 History for Boa constrictor : this is mentioned to show how remotely it is possible 

 to diverge from accuracy in thii science. 



Vol. I. ...No. 3. 21 



