418 



KANSAS UNIVERSITY SCIENCE BULLETIN. 



Ancistrodon piscivorus Lacepede. 



Water Moccasin. 

 Crotalus pisoivorus Lacepede, Hist. Serp., II, 1787, p. 424. 

 Scytalus piscivorus Latreille, Hist. Nat. Rept., Ill, 1801, p. 163. 

 Coluber aquaticus Shaw, Gen. Zool., Ill, 1802, p. 125. 

 Toxicophis pisoivorus Baird and Girard, Cat. N. Amer. Rept., Pt. I, Serp. 



1853, p. 19. 

 Awinlrorlon piseivorus Cope, Proc. Acad. Nat. Sci. Pliila., 1859, p. 336. 



Flu. 35. 

 Ancistrodoa piscivorus Lacepede. 



No loreal. Inferior wall of orbit constituted by third labial ; 

 twenty-five dorsal rows. Dark chestnut brown, with indistinct 

 vertical dark bars. Line from superciliary along the edge of 

 the head, through the middle of the second supralabial row. A 

 second line from the lowest point of the orbit parallel to the first. 



Scales all large and well developed ; those on the sides and 

 back of head conspicuously so. Two nasal plates, with the nos- 

 tril between them. Anterior orbitals two, one above the other ; 

 the upper extending from the eye to the posterior nasal, the 

 the lower linear and forming the upper wall of the pit. Lower 

 and posterior wall of pit constituted by a narrow plate resting 

 along the third labial and terminating in the second. Third 

 labial very large, constituting the inferior wall of the orbit, of 

 which three scales form the posterior. Upper labials eight, 

 very large and broad; lower ten. Occipitals terminated each 

 by a triangular plate. All the scales on the back of the head 

 carinated. Gastrosteges 130-145. Urosteges 39-45. 



General color dark chestnut brown, with darker markings. 

 Head above purplish black. An obsolete chestnut-brown streak 

 passes from the posterior end of the superciliary along the upper 



