Reptiles and Amphibians of Illinois. 311 



OROTALUS, LiNIf. 



Linnaeus, Ace. Mus. Adolph. Frid., 175't, p. 39. 

 Bd. and Gir., Cat. N. A. Kept., Ft. I., 1853, p. 1. 



Head deficient in cephalic plates, the frontal and parietals 

 being absent and their place being occupied by small scales 

 like those on the body. Pit between the eye and nostril large. 

 Fangs and poison glands well developed. Supralabials sep- 

 arated from the orbit by thi;ee or more series of small plates. 

 Dorsal scales in from twenty-one to thirty-one rows, carinated. 

 Subcaudals entire or with one or two posterior divided. Rattle 

 present. Body moderately stout. Tail short. 



Orotalus horridus, Linn. Timber Rattlesnake. 



Crotalus horridus, Linn., Syst. Nat., ed. 10, 1758, 1., p. 214. 



Crotalus durissus, Ilolbr. N. A. Herp., 1842, III., p. 9, pi. 1. — De 

 Kay, Nat. Hist. N. Y., I., Zool. III., Kept, and Amph. 1842, p. 

 55, pi. 9, fl?. 19.— Kenn. Trans. III. State Agr. Soc, 1853-54, 

 I., p. 592.— Bd. and Gir., Cat. N. A. liept.. Ft. I., 1853, p. 1. 



Candisona. horridd, Cope, Free. Acad. Nat. Sci. Fhila., 1866, p. 309. 



Crotalus horridus, Davis & Rice, Bull. 111. State Lab. Nat. Hist., 

 L, No. 5, 1883, p. 27 ; Bull. Chicasfo Acad. Sci., 1883.— S. Gar- 

 man, Mem. Mus. Comp. Zool., 1883, pp. 115, 174, pi. 9, flg. 1. 



Large, reaching a length of six feet. Body moderately short. 

 Neck contracted abruptly behind the head. Tail short, com- 

 pressed, not tapering. Rostral plate small, narrowed above. 

 Two nasals, the anterior larger. Two or more loreals. Two 

 anteorbitals, the superior larger, the inferior smaller and form- 

 ing the superior margin of the pit. About five postorbitals and 

 suborbitals, the latter separated from the supralabials by two 

 rows of scales. Supralabials fourteen, first and fifth (fourth in 

 some examples) largest. Fifteen infralabials. A pair of large 

 elongate submentals. Dorsal scales carinate, excepting the 

 outer rows, which are smooth or obsoletely carinate in front, 

 in from twenty-three to twenty-five rows. Ventrals 165. Sub- 

 caudals 23, the first and last paired. 



Color above brownish yellow to almost black, posteriorly 

 with transverse zigzag bands of chestnut-brown, edged with 

 black and bordered outside the black with yellow, anteriorly 

 with three series of brown spots bordered in the same manner. 



