156 Trans. Acad. Sci. of St. Louis. 



the tail of a mud-eel (Siren lacertina) sticking out of its 

 mouth. When disgorged, the head of the eel had been 

 nearly digested. A female which I found in Randolph 

 County, 111., gave birth to thirteen young ones on Sep- 

 tember 4th. From one of these the above color descrip- 

 tion was made. 



48. Natrix sipedon" Linnaeus. Common Water Snake. 

 Water Moccasin. 



Natrix fasciata sipedon, Tropidonotus sipcdon, Tropidonotus fasciatus 

 sipedon, Tropidonotus sipedon sipedon, Nerodia sipedon, Nerodia 

 sipedon sipedon, La Couleuvre sipede, Coluber sipedon. 



Description. — Rostral wider than high, only a small portion visible 

 from above. Internasals wedge-shaped, longer than wide. A single 

 nasal with a groove below the nostril. Sometimes apparently two 

 plates with the nostril between them. Loral quadrangular, higher than 

 long. Prefrontals wider than long. One large anteorbital, its superior 

 angle reaching nearly to the frontal. Frontal narrow, sides concave, 

 much longer than wide — one and one-half times longer than wide. Parie- 

 tals short and broad. Superciliaries narrow in front. Postorbitals 

 three. Upper labials eight or nine; often eight on one side and nine 

 on the other. Eye above the fourth and fifth labial; sixth and seventh 

 the largest. Temporals 1-3. Lower labials 10; fifth and sixth the 

 largest. Fifth labial in contact with anterior chin-shield. Head dis- 

 tinctly marked off with a more slender neck. Body moderately slender. 

 Tail cylindrical, tapering and of moderate length. Twenty-three rows 

 of dorsal scales, all keeled, with the exception of the outer row, which 

 is only slightly keeled, being nearly smooth. Ventrals 138. Anal di- 

 vided. Subcaudals 60 pairs. 



Color. — A dorsal series of large brown spots, three to five scales long, 

 separated by light interspaces of one-half to two scales long. Alternat- 

 ing with the dorsal spots are lateral spots of the same color. These 

 spots are one and one-half to two and one-half scales long, reaching into 

 the ventrals. These side spots are separated by lighter interspaces from 

 two to three scales long. Anteriorly the latter spots are often indis- 

 tinct, becoming frequently confluent with the dorsal spots, forming 

 cross bands. Belly maculated by many brown spots bordered with 

 black. Spots more numerous posteriorly. In old specimens the general 

 color markings are obscured and the snake appears plain brown. Top 

 of head brown. Upper part of upper labials brownish, like the head, 

 lower part yellowish. Lower labials, chin and throat yellowish. Poste- 

 rior edge of upper and lower labials with a dark streak. 



Habitat. — Eastern United States west to western Mis- 



