1186 



REPORT OF NATIONAL MUSEUM, 1898. 



Uropsoplius durissus Gray, Cat. Brit. Mns., 1849, p. i9 (exclus. cit. Lmiifeus and 

 boinonynis covjiuentus Say, r/iom6i/f r Latreille, /r(.seri«/?/sWiegmann, Wagler. 

 and Gray). 



f Crotalus catesbcri Hemprich, Fitzinger, Neue Class., p. 63, according to Gray 



? Urocrotalon catesbyanum Fitzinger, Diesing, Syst. Helmintli., II, 1851, p. 431. 



Figures, Catesby, Hist. Car., II, pi. xlii. — Lacep^de, Serp., II, pi. xviii, fig. 

 3. — Shaw, Zool., Ill, pi. lxxxviii.— Daudin, Hist. Rept., V, pi. lxviii. — 

 GUERiN, Iconogr. R. Animal, pi. xxiii, fig. 2. — Schlegel, Essai, pi. xx, figs. 15, 

 16; Diet. Univ. Hist.Nat. Atlas, II, pi. xiii, fig. 7. — DuMi^.RiLand Bibron, Erp. 

 Gen. Atlas, pi. lxxxiv bis. fig. 7. — Holbrook, N. Am. Herp., III. pi. i. — De 

 Kay, Zool. New York, Pt. 3, Atlas, fig. 19.— Baird, Serp. N. Y., pi. i, fig. 1 ; U. S. 

 Pac. R. R. Expl. Rept., X, Reptiles, pi. xxiv, fig. 1. 



Habitat. — Eastern United States to the Plains. 



Fig. 342. 



Crotalus horridus Linn.eos. 



= 1. 



Kansas. 



Cat. No. 4621, U.S.N. M. 



Upon the top of the extremity of tbe muzzle tbere are two subtri- 

 augular shields (iDternasals) in contact with eacb. other. A large oval 

 shield covers the region over each eye (superciliary). These shields 

 are in contact anteriorly with the j)refronta], and forms upon each side 

 the external shield of a cross series (postfrontals) immediately behind 

 the prefrontals, which is usually composed of five plates. The remaining 

 part of the upper surface of tbe head is covered with small subtuber- 

 culous scales. 



The shields bounding the upper lip (superior labials) are from twelve 

 to fourteen in number, the fourth or fifth the largest; those bounding 

 the lower lip (inferior labials) thirteen to fifteen. Three rows of scales 

 separate the eye from the superior labials. Two plates iu front of the 

 eye (preoculars), the lower usually reaching the pit in the side of the 

 face; the upper larger and separated from the hinder of the two plates, 

 between which the nostril is pierced (nasals) by two or more small 

 plates (loreals). The scales of the body are in twenty-three or twenty- 



