64G NORTH AMERICAN SNAKES COPE. 



dice may be ascribed to several causes. One of these is tlieir ,m'eat 

 fecundity. Prof. Baird raentious a specimen of E. sirfalis whicii pro- 

 duced eighty young at a birth. Another cause is their readiness to seek 

 concealment in water, so that they most readily escape observation. 



Several of the species are pugnacious in their disposition. Such is 

 the case with the two which have the widest distribution and greatest 

 abundance of individuals, the E. sirtalis L, and E. elegans Bd. and Gird. 

 Their bite, it is needless to remark, is perfectly harmless. Some of the 

 species possess great elegance of form, as those of the E. saurita group. 

 Others have much brilliancy of color, as the metallic green of some 

 forms of the E.proxima and E. sackenii^ and the red and black of the E. 

 sirtalis concinna. 



The species differ as follows : 



I. Second and usnaily the first row of scales keeled ; lateral stripe on tbird and fourth 



rows. Orbit bounded below by two or more labials. 



1. Temporal scales 1-2. 



* Tail e(inal or exceeding one-tbird total lengtb ; first row of scales mncb 



longer than deep, strongly keeled; scales in 19 rows. 

 Superior labials eight, longer than bigh ; very slender; color metallic olive. 



E. sackenii. 

 Superior labials seven, longer than higb ; very slender; color brown. 



E. saitriia. 



* * Tail less than a third and more tlian a fourtb the total length • superior 



labials eigbt. 

 Head Hat ; superior labials longer than high ; scales in nineteen rows ; inferior 



row keeled, longer than deep E. proxima. 



Head elevated, superior labials bigbor than long; scales in 21 rows, those of 



inferior row as deep as long E, megalops. 



* * * Tail more than one-fourth, and not less than one-fiftb the total length ; 



scales in 21 rows, tbe inferior row as deep as long, and weakly or not 



keeled. 

 Superior labials seven ; tail less tban four and five tenth times in total 



length E, radix. 



Superior labials eigbt ; tail more than four and five tenth times in total length. 



E. inacrosleitima. 



2. Temporal scales 1-1. 



Tail between one-fiftb and oue-fourtb tbe total length ; superior labials seven ; 

 bead little distinct; yellow black bordered lateral stripe on second, 

 tbird, and fourth rows of scales E. hutlerii. 



Tail between one-fourth and one-third the total lengtb ; superior labials eight ; 

 head quite distinct; lateral line faint, on third and fourtb rows. 



E. 1-utiloris. 



II. Second row of scales keeled ; the first keeled or smo.)tb. Orbit above two labials. 



Lateral stripe, when present, on second and third rows of scales. 

 1. Temporal scales, 1-2. 



* Scales in twenty-one (:i) rows ; superior labials, eigbt. 



Two preocnlars; superior temporals small; first row of scales keeled ; black, 

 stripes indistinct; head short, frontal wide E. bisciitala. 



One preocular; superior temporals small; bead short, frontal wider, not 

 touching i)reocular, posterior labials higher than long; tail three and 

 one-third to four and two-third times in lengtb E. elegans. 



One preocular ; a largo superior temporal bounding occipital ; frontal narrow, 

 touching preocnlars; liead long, labials all longer than high; tail 

 three and one-fourth in length E, angustirosiris. 



