CROCODILIAN^, LIZARDS, AND SNAKES. 1151 



and may be performed by the snake's liead when severed from the 

 body. I had a narrow escape from being bitten in this way by the 

 head of a Crotalus molosHus, which was attached to the body by skin 

 only. 



Eattlesnakes live in all kinds of ground, but naturally persist longest 

 in rocky regions, where they have abundant i)laces of concealment. 

 Some of the si)ecies grow to a very large size, particularly the C. ada- 

 mantoii.s of North and the C. (lurissus of South America. The former 

 is probably the larger of the two; at least we have information of 

 larger specimens. I am credibly informed that specimens have been 

 found on the islands off the Gulf coast of Florida of 8 feet in length. 

 Some specimens of the western subspecies G. a. atrox also reach a large 

 size. The third species in dimensions is the C. horridns, which grows 

 on the coast of North Carolina to a length of 5 feet and proportionate 

 thickness. The species of the plains, C. confluentus, rarely reaches so 

 large a size. Its gray-greenish color readily (!onceals it in the sparse 

 vegetation and it is only observed when closely approached. It is very 

 abundant north of the Missouri River and extends north to the Sas- 

 katchewan, beyond the line of distribution of any other species. 



From the effective character of their weapons of offense and defense, 

 rattlesnakes have a great advantage in the struggle for existence 

 against all animals except man and his domestic companion, the jug. 

 Hence in unsettled localities in North America they are abundant, 

 especially in the warm regions of the South and West. In many 

 places they are the most abundant species of snake, as, for instance, 

 on the plains, where no s])ecies is as often seen as the Crotalus conjlu- 

 entus. That they have been much more abundant in many wild parts 

 of the East than at present, is indicated by the great quantities of their 

 bones which are found in the caves of the limestone regions of the 

 Mississippi Valley. The pig, as is well known, will destroy and eat rat- 

 tlesnakes with impunity. It is said that the poison is not sufficiently 

 introduced into the circulation to cause death, owing to the thick adi- 

 l)ose layer with which the domesticated pig is covered. 



The following synopsis of the characiters of the species of Crotalus is 

 the result of long familiarity Avith them. Some of the forms originally 

 regarded as species are treated as subspecies, owing to the evanescence 

 of their characters. In spite of the subdivision of their head plates, 

 the homologues of the plates of harndess snakes maybe traced. Thus, 

 there are from two to three preoculars and from one to four loreals. 

 The nasals are never more than two, and the nostril is always between 

 tliem. There is one ])air of geneials. The species of Section I display 

 homologues of internasal and prefrontal plates, while the same, more 

 divided, are seen species of Section II. 



The transitional forms or subspecies in this genus, as is usually the 

 case, furnish instructive evidence as to the evolution of the chaiacter 

 of the species. It is not imiirobable, as already remarked, that their 



