304 Illinois State Laboratorij of Natural History. 



Variety niger. 



Nearly uniform brown, or bluish black, lar^e. 

 Southern Illinois. Belleville, Mt. Carmel (Nat. Mus.), 

 Saratoga. 



A singular species known everywhere as the spreading 

 adder from its habit of expanding the head and neck when 

 disturbed. From its threatening behavior it is thought to be 

 poisonous, but it has no fangs and is consequently perfectly 

 harmless. I have seen the variety niger when suddenly 

 exposed by turning over a log under which it was concealed, 

 lash the body about violently and cast a yellowish ma- 

 terial from its mouth, at the same time hissing and expanding 

 to its greatest capacity. This variety when struck a sharp 

 blow, will sometimes pretend to be mortally wounded, casting 

 itself upon its back and persistently returning to that position 

 when placed belly downward. 



Heterodon simus, Linn. Hog-nose Snake. 



Var. simus. 



Coluber simus, Linn., Syst. Nat., ed. 12, 1766, 1., p. 875. 

 Heterodon simus, Holbr., N. A. Herp., 18^2, lY.', p. 57, pi. 15.— 



Bd. and Gir., Cat. N. A. Kept., Pt. I., 1853, p. 59. 

 Heterodon simus, subsp. slnius, Davis and Rice, Bull. 111. State 



Lab. Nat. Hist., I.. No. 5, 1883, p. 44; Bull. Chicago Acad. 



Sci., 1883. 

 Heterodon simus, S. Garman, Mem. Mus. Comp. ZooL, 1883, pp. 



16, 160, pi. 6, fig. 4. 



Var. nasicus. 



Heterodon nasicus, Bd. and Gir., Stausbury's Expl. and Surv., 

 Val. Great Salt Lake, 1853; Cat. N. A. Kept., Pt, L, 1853, pp. 

 61, 157. 



Heterodon simus var. nasicus, S. Garman, Mem. Mus. Comp. 

 Zool., 1883, pp. 77, 160, pi. 6, fig. 6. 



Small. Body stout. Head large, convex above. Tail 

 very short, cylindrical, tapering. Dorsal scales all carinate ex- 

 cepting the outer row of each side; scales of the row next the 

 outer with very faint carinas on their basal portions. Rostral 

 plate produced forward and upward, its anterior face flat, 



