Toxicornis. 19 



Genus TOXIC OPIIIS, Troost. 



Gen. Char. No rattle. Pit and fangs as in Aghistrodon. Eleven 

 plates on top of head. No loral plate between nasal and anterior 

 orbital. A second and smaller pair of occipital plates contiguous to 

 the first. Labial entering into the orbit. Scales very conspicuously 

 carinated, forming 25 longitudinal rows. Subcaudal scutellas divided 

 posteriorly. Habits aquatic. 



Syn. ToxicopMs, Troost, Ann. Lye. Nat. Hist. N. York, IH, 

 1833, 190. 



1. ToxicopMs piSCivorus, B. & G.— No loral. Inferior wall of 

 orbit constituted by 3d labial : 25 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 supra labial row. A second line 

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



Syn. Trigonocephalus piscivorus, Holer. N. Amer. Herp. II, 1838, 63. 

 PI. xiii. and 2d ed, III, 1842, 33. PI. vii. 

 Water moccasin. 



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

 of head conspicuously so. Two nasal plates with the nostril between 

 them. Anterior orbitals two, one above the other ; the upper ex- 

 tending from the eye to the posterior nasal, 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 3d labial, and termi- 

 nating on the 2d. Third labial very large, constituting the inferior 

 wall of the orbit, of which three scales form the posterior. Upper 

 labials 8, very large and broad : lower 10. Occipitals terminated 

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

 carinated. Dorsal scales all carinated. 



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 edge of 

 the head, through the middle of the 2d row of supralabial scales. 

 A narrow yellowish white line passes from the 3d labial, or begins 

 just below the lowest part of the orbit, and passing backward, paral- 



