212 



NORTH AMERICAN FAUNA. 



[No. 7. 



absence or presence of spots is only due to the darker or lighter shade 

 of the ground color. 



A great amount of collecting and observing will have to be done 

 before we can know anything definite about the individual variation of 

 these snakes. Each species and form will have to be investigated by 

 itself, for it is plain that conclusions based upon analogies from allied 

 forms are not to be relied upon, and it seems as if the only safe way 

 would be to commence an examination on as large a scale as possible of 

 the unborn young, cut out of the mother snake. A careful and detailed 

 record of such examinations would settle many a mooted point, and is 

 recommended to the attention of California naturalists. 



List of specimens of Thamnophis elegans. 



U.S. 

 Nat. 

 Mas. 

 No. 



Sex and 

 age. 



Locality. 



Alti- 

 tude. 



Date, 



Collector. 



Kemarks. 



18708 



ad. 





Feet. 



4,000 



Aug. 6 

 Aug. 31 



...do 



Nelson 



Dutcher 



do 





18709 

 18710 



10 miles south of Mount Whitney, 



Calif. 

 do 



















Thamnophis hammondii (Kenn.). 



Fortunately there attaches no doubt to specimens belonging to this 

 well defined species, and all here referred to it are typical in every 

 way, scutellation as well as coloration. Its range overlaps to a great 

 extent that of* Th. vagrans without affecting the purity of the type, 

 and as both are fouud in the identical localities, as well proved by 

 the present collection, there seems no valid reason for regarding them 

 as subspecies of the same species. The distinctive characters of this 

 form are well pointed out and emphasized by Kennicott in the original 

 description. 



Neither does there seem to be any good reason for substituting the 

 name Th. couchii for that of Th. hammondii. The two forms have been 

 considered distinct up to the present time, and there has been collected 

 no additional material of recent years which could tend to show that 

 they are identical. 



The twelve specimens of Th. hammondii contained in the present 

 collection show a great constancy of some of the structural characters. 

 All have twenty-one scale rows, eight supralabials, and one preocular. 



In nearly all of them there are distinct indications of a dorsal band 

 which in No. 18691, a young specimen, is quite well marked the whole 

 length of the animal, while in most others it is chiefly developed on 

 the portion nearest to the head. 



