1884.] iJd [Cope. 



iiEPTOGNATHUS CATESBYI D. & B. 

 OXYRRHOPUS RHOMBIFER D. & B. 



OxTRRHOPUS piiUMBEUs Wied. 



Ltstrophis dorbignyi Dum. & Bibr. Heterodon dorhignyi Dum. &Bibr. 

 The generic name Lystrophis is now proposed for the Heterodontes of 

 Dumeril and Bibron, which have smooth scales and a divided anal plate. 

 Catachlein has been already proposed by Jan. for the smooth species with 

 entire anal plate. 



Xenodon rhabdocepiialus Boie. 

 Xenodon neovidii Giinth. 

 Helicops ixprat^niatus Jan. Iconograpbie Opliidiens, Livr. 28, 1868. 



PI. iii, fig. 3. Helicops trwittatus Cope. Proceeds. Am. Philos. Soc, 



1877, p. 93. 

 One side of the head of the single specimen displays but seven superior 

 labials ; the other side eight. Both sides display two loreal plates, one 

 above the other. 



Helicops baliogaster, sp. nov. 



Scales in nineteen longitudinal rows ; those of six rows on each side as 

 wide as, or wider than long : all keeled except those of the first row on 

 each side, the second very weakly. Dorsal scales finely striate. Head 

 little distinct, muzzle very short. Nostrils superior. Each nasal plate and 

 the loreal higher than long. Preocular very narrow ; two postoculars, 

 each longer than deep. Internasal small ; prefrontals wider than long. 

 Frontal long with parallel sides, occipital rather long. Temporals 2 — 2, 

 the superior of the anterior pair only reaching the postoculars, and in con- 

 tact with both of them. Superior labials eight, the fourth only entering 

 the orbit. Inferior labials eleven, seventh largest, and the last one in 

 contact with the postgeneials, which are about as long as the pregeneials. 

 Total length, M. .587 ; of mouth to canthus, .017 ; of tail, .114. Gastro- 

 steges, 128 ; one divided anal ; scutella, 69. 



Superior and lateral surfaces to the middle of the second row of scales 

 blackish brown, with a lighter brown band on the sixth and adjacent 

 halves of the fifth and seventh rows. A yellow lateral band on the 

 adjacent halves of the first and second rows of scales. Belly black with 

 one or two square yellow spots on the middle portions of most of the gas- 

 trosteges, which are sometimes so arranged as to leave a black spot in the 

 middle, which together form parts of a median black band on the thoracic 

 region. Tail with a median black band below. A dark cross-band con- 

 necting the corners of the mouth across the throat. In a young specimen 

 this cross-band connects the ends of two longitudinal black stripes, which 

 extend from each penultimate inferior labial. A black band on each side 

 of the geneials connected by a cross-bar across the ends of the postgeneials. 

 In the younger specimen the dark brown of the back is lighter, and each 



PROC. AMER. PHILOS. SOC. XXII. 118. Y. PRINTED MARCH 9, 1885. 



