Reptiles and Aji/phihians of lUhiols. 281 



spots near the outer margins of each ventral scute, forming 

 two longitudinal series. Sometimes with a broken median 

 series of spots. Cephalic plates faintly margined with yellow. 

 Labials and scales of the under side of the head, each with a 

 black central spot. 



Attains a length of more than 'M^ inches. 



Southern Illinois. '' Found north to Mt. Carmel at least." 

 (Ridgway.) 



Hydrops abacurus, Holbr. Red-bellied Horn Snake. 



Coluber abactirus, Holbr., N. A. Herp., 1836, 1., p. 119, pi. 23. 

 Helicops abacurus, Holbr., N. A. Herp., 1842, III., p. Ill, pi. 26. 

 Farawda ahacurns, Bd. and Gir., Cat. N. A. Rept., Pt. I., 1853, 



p. 123. 

 (U(l()j)isma abamnnii. Dum. et Bibr., Erp. Gen., VII., 1854, p. 342. 

 Hydrops abacunis, Dum. et Bibr., Erp. Gen., Atlas, pi. 65. 

 Fa rancid abaeura, Davis and Rice, Bull. 111. State Lab. Nat. 



Hist., I., No. 5, 1883, p. 32; Bull. Chicago Acad. Sci., 1883. 

 Hydrops abacurus, S. Garman, Mem. Mus.Comp. Zool., 1883, pp. 



36, 144, pi. 1, fig. 5. 



Body tapering very slightly toward the extremities. 

 Neck thick, as wide as the head. Head small. Tail of mod- 

 erate length, maintaining its diameter well toward the tip and 

 tapering suddenly, the tip covered by a conical nail. All the 

 scales smooth and shining. Rostral plate wide. But one iu- 

 ternasal. Two large prefrontals, each forming a part of the 

 boundary of the orbit of its side. Frontal large, elongate. 

 Supracilianes small. One nasal, grooved below the nostril. 

 A single elongate loreal which forms part of the anterior boun- 

 dary of the orbit (some authors consider this an anteorbital 

 and describe the species as without a loreal). No anteorbitals. 

 Two postorbitals, the lower much the smaller. Parietals large, 

 bounded exteriorly by two elongate temporals. Six or seven 

 supralabials, the eye above the third and fourth, fifth and sixth 

 largest. Infralabials eight or nine, the fifth largest, those fol- 

 lowing it becoming rapidly smaller, the last smallest of all. 

 Dorsal scales in nineteen rows, large, the outer scales wider 

 than long. Ventrals 168-203, the one preceding the anals 

 divided. Sabcaudals in 35-49 pairs, a few of those behind the 

 vent sometimes united. 



