102 



lower; while above they join the contiguous corners of the dorsal 

 blotches. Of these blotches about 32 lie in front of the vent. Occa- 

 sionally there is a little confusion in the relations of the blotches of the 

 different series, but not much. The belly is yellowish white, with a few 

 triangular spots of black, giving it a speckled appearance. The head is 

 smoky brown above as far down as the upper edges of the upper labials. 

 The lower edges of these are yellow, with a black border on the hinder 

 edge. The lower labials are similarly yellow, with black posterior edges. 



The size is about that of Natrix sipedon, 2 feet 8 inches or more. 



This species is distributed from Michigan to Louisiana and Texas. 

 There is a specimen of it in the National Museum from Lafayette Oth- 

 ers have been sent there by Mr. Robert Ridgway from Wheatland. I 

 have seen another specimen in Mr. Sampson's collection made at New 

 Harmony. It is no doubt generally distributed throughout the State. 



Of the habits of this species I know nothing, except that it is an 

 aquatic snake. 



Genus HETERODON, Beauv. 



Heterodon, Pal. de Beauvais, 1802, 57, iv, 32 ; Holbrook, 1842, 54, iii, 

 37 ; Baird & Girard, 1853, 6, 51. 



Body short and stout. Neck nearly as thick as the head. Tail 

 short. Head broad, short and high. Head, neck and body capable of 

 great flattening. Outline of mouth much curved, rising behind the 

 eyes. Posterior teeth longer and fang-like. Snout projecting beyond 

 the mouth, shovel shaped. The rostral with a sharp horizontal edge 

 and a longitudinal ridge above. This followed behind by a small azy- 

 gous plate. Upper labials cut off from contact with the eyes by sub- 

 orbital plates. Dorsal scales keeled. Anal plate divided. 



Key to the Species op Heterodon. 



Prefrontals separated by the azygos only. M. platirhmos, p. 102. 



Prefrontals and sometimes postfrontals separated by a number of 



small plates. H. shims, p. 105. 



Heterodon platirhinos, Latr. 



Sog-nosed Snake; Spreading Viper. 



Heterodon platirhinos, Latreille, 1802,57, iv, 32; Holbrook, 1842, <54, 

 iv, 67, pi. 17; H. platyrhinoi<, Baird & Girard, 1853, 6, 51; Garman, 

 1883, 18, lb, pi. 6, fig. 5; Heterodon niger, Troost, 1836, 62, iii, 186; 

 Baird & Girard, 1853, 6, 55. 



Body stout and heavy. Tail about one-fourth the entire length, often 

 shorter. Head rather broad and short, but quite deep. The usual nine 

 crown-shields pi'esent. In addition, there is an azygous plate between 



