206 Trans. Acad. Sci. of St. Louis. 



tail like a rattlesnake, but in a slower rhythm, and retreats 

 to the water for safety. When upon a higher log, they 

 tumble headlong into the water when alarmed. The Cot- 

 ton Mouth lives on fish, frogs, birds, smaller mammals, 

 and other snakes, but it is said not to devour its own kind. 

 Dogs and cattle bitten by this snake become very sick, 

 but recover in a very short time. Notwithstanding the 

 fact that the poison of the Moccasin has been found pro- 

 portionately less virulent than that of the Rattle Snake 

 and Copper Head, the fear it inspires is well founded for 

 it is much larger and heavier snake than the Copperhead. 

 The snake is ovoviviparous. It brings forth from two to 

 seven young at a time, which show the color pattern to 

 perfection. A Cotton Mouth, which I caught July 3rd, 

 near Bertig, Dunklin Co., Mo., gave birth to six young 

 ones on September 18th. 



Dates of capture. — April 24 ; July 3 ; September 5. 



81. Agkisteodon contoetrix Linnaeus. Copperhead. 

 Moccasin. 



Boa contortrix, Ancistrodon mokason, Scytale contortrix, Cenchris 

 mokeson, Scytalus cuprens, Cenchris marmorata, Cenchris contor- 

 trix, Trigonocephahis cenchris, Trigonocephalus contortrix, Anci- 

 strodon contortrix, Acontias atrofusciis, Trigonocephalus atrofus- 

 cus, Trigonocephalus historionicus, Ancistrodon atrofuscus. 



Description. — Rostral broad and high. Two internasals. Generally 

 three prefrontals, the median small. Frontal pentagonal, as wide as 

 long. Parietals about the size of the superciliaries, showing a ten- 

 dency to break up into small shields. Nasal divided with nostril be- 

 tween. Loral present, separating the posterior nasal from the supe- 

 rior ante-orbital. Ante-orbitals three, the inferior one very small. Post- 

 orbitals 3-4. Eye entirely separated from the labials by the sub- 

 oculars. Upper labials eight (seven), the second twice as high as 

 long, bounding the pit in front and reaching the loral. Lower labials 

 nine or ten. Head v/ide, flat, triangular with the sides in front of the 

 eyes vertical, with a sharp canthus rostralis. Body less stout than in 

 A. piscivorus. Tail short, tapering, about one-eighth the total length 

 and ending with a curved horn or nail. Dorsal row's 23, strongly 

 keeled. Ventrals 145-155. Anal entire. Subcaudals 31 to 52, all entire 

 except the last 8 to 18 pairs. 



