862 REPORT OF NATIONAL MUSEUM, 1898. 



is found in the Austrocential and Austrotcideutal districts, as well as 

 in the Chihuahuan of the Sonoran subiegion. The U. lineaUcollis is 

 also reported by Giiuther from D urn as, in Guatemala. 



Though this species differs widely in color characters from the E. 

 pleiirostictus it resembles it closely structurally. Boulenger i^laces the 

 two in different sections of the genus Coluber, one of which is charac- 

 terized by a more, and the other by a less, distinct vertical augulatiou 

 of the ends of the gastrosteges. I, however, find no difference between 

 the two species in this respect. The following characters may, how- 

 ever, be noted : The head in the E. lineaUcollis is larger relatively to 

 the general dimensions than in the E. pleurostictus. Thus the cephalic 

 plates are of equal length in two specimens of these species, of which 

 the E. lineaUcollis measures 950 mm. and the E.pleurosUctus, 1,145 mm. 

 The gastrosteges and urosteges are more numerous in the E. lineaU- 

 collis. In this species there are in two specimens, gastrosteges 242, 

 urosteges 72, and gastrosteges 234, urosteges 69. Boulenger counts 

 244 + 69. In two specimens of E. pleiirosUctus I find, gastrosteges 

 228, urosteges 58, and gastrosteges 221, urosteges 54. Boulenger 

 gives gastrosteges 209-233, urosteges 51-67. My three specimens 

 of E. lineaUcollis, like Giinther's, have twenty-seven rows of scales, 

 and the three of E. pleiirosUctus before me have twenty-nine. Of 

 seven specimens of the latter in the British Museum three have 

 twenty-nine rows and four twenty -seven, according to Boulenger. 

 Finally, the relations of the frontal and supraocular i^lates differ in the 

 two. In the E. lineaUcollis the supraoculars are narrow and the frontal 

 wide; in the E. pleurosUcUis the supraoculars are relatively wider. 

 The shorter head of the latter species is shown in the loreal, which is 

 as deej) as long, while in the E. lineaUcollis it is a little longer than 

 deep. 



Measurements. — The longest specimen of this species in the U. S. 

 National Museum measures 1,320 mm.; tail, 190 mm. The British 

 Museum specimen measures 1,500 mm. The longest E. pleurostictus 

 (Cat. No. 9005) in the U. S. National Museum measures 1,145 mm.; 

 tail, 165 mm. The British Museum catalogue gives 1,690 mm. as the 

 greatest length. 



RHINECHIS Michahelles. 



Bhinechis Michahp:lles, in Wagler, Icones et Descript. Amphib., 1833, pi. 25. — 

 BuNAi'ARTE, Fauna Italica, 1838, pi. 70.— Dumeril and Bibron, Erp. Gen., 

 VII, 1854, p. 227— Cope, Bull. U. S. Nat. Mus., No. 32, 1887, p. 56. 



Arizona Kknnicott, U. S. and Mex. Bound. Surv., II, 1859, Reptiles, p. 18. 



Head moderately distinct, muzzle depressed, projecting. Tail rather 

 short. Teeth equal. Cephalic plates normal; the rostral recurved and 

 deeply separating the elongate internasals. Pupil round. Scales 

 smooth, bifossate. Anal and subcaudal scuta entire. 



The production and recurvature of the rostral plate and entire anal 

 plate distinguish this genus from Coluber, which it resembles. It was 



