NATURAL SCIENCES OF PHILADELPHIA. 809 



Two pairs geneials ; occipitals short and broad. Dark brown, -with numerous 

 lighter or darli gray cross bands, which are blacked edged, and extend to the 

 first row of scales, and are sometimes interrupted on the vertebral line. Belly 

 with a broad brownish gray band from throat to vent, the ends of the gastro- 

 steges yellow, forming two bands ; a median longitudinal brown line on the 

 tail. 



Tail 3-3 times in length. The plates of the head and other peculiarities are 

 quite like those of H. a n g u 1 a t u s. 



From Surinam, Mus. Academy Natural Sciences. Discovered by Chas. 

 Hering, M.D. 



Helicops CYCLOPS Cope, sp. nov. 



Scales in nineteen rows, strongly keeled everywhere, including the first row. 

 Two pairs geneials ; occipitals short and wide, long as frontal. 



Head exceedingly short, mouth wide as the length of the rounded lip mar- 

 gin. Superior labials eight, fourth scarcely entering orbit by its upper corner 

 (by its whole extremity in H. a n gu 1 at u s), the fifth, sixth and seventh nar- 

 row and high. Prefrontals broad as long (much broader than long in H. a n g u- 

 latus). Orbitals 1 — 2, nearly meeting below orbit. Temporals 2 | 1 | 3 

 (1 I 1 I 3 in H. a ng u 1 a t u s). Loreal plate wide as high, (higher than wide 

 in H. a n g u 1 a t u s). 



Tail -33 total length, slender (less than -25, H. angulatus). Gastrosteges 

 124, anal 1 — 1 ; urosteges 89. 



Light yellowish brown, with twenty-six transverse deep brown rhombs 

 across the back which terminate at the second row of scales, being separated 

 from the back ventral cross-bar, which is opposite each, by a longitudinal yel- 

 low band. This band is not distinct between the spots. Belly strong yellow 

 with jet black cross bars, which are on more than two gastrosteges. Tail 

 black, spotted below. A brown cross-band between the eyes. 



Length 27-5 inches. From Bahia, Brazil. Mus. Academy, from Dr. Otho 

 Wucherer. 



This species is at first sight much like the H. angulatus, but differs vari- 

 ously as above. In coloration the spots in the latter are always continued into 

 the ventral cross-bars, and not interrupted as in A. c y c 1 o p s. 



The species of the genus are as follows : H. carinicauda Nieuw. H. 

 modestus Gthr. H. leprieurii Dum. Bibr. H. chrysostictus 

 Cope. H. in f r a t ae n i a t u s Jan. H. f u m ig a tu s Cope. H.cy clops 

 Cope. H. an g ul a t u s Linn. H p o 1 y 1 e p i s Gthr. The following s])ecies 

 have been erroneously referred to this genus : //. waffleriJun. is Tretanorhinus 

 variabilis Dum. Bibr. //. agassizi Jan. is T. n i g r o 1 u t e u s Cope, //•. 

 Kc/datosus Jan. is Atretium s c h i s t o s u m Daudin, and //. mortuarius Jan. is 

 Tropidonotus m or tuarius (Boie) Schlegel [Tropidinotus ferox Giinther). 



Thrasops pr.^stans Cope. 



The largest species of the genus, exceeding considerably the T. fl avigu- 

 lari s of Hallowell. The length of one sp. is 6 ft. 3 in., of which the tail is 

 2 ft. Si in., while the body of another measures 4ft. 6 in., giving a total of 

 seven ft. 1 in. Length head to end of quadratum In in. 10 1., width between 

 superciliary margins 8 lines, diameter orbit 4 1. ; from orbit to end of muzzle 

 )) lines. 



The head is very distinct, and the muzzle rather short for the genus ; the 

 eyes are very large. Rostral plate small, postnasal lower than prenasal ; place 

 of the loreal entirely occupied by the prefrontals Orbitals 1 — 2, tlie anterior 

 not quite reaching the frontal. Frontal one-sixth longer than wide in front, with 

 concave sides and short posterior angle. Occipitals broad, short, divaricate 

 behind; temporals 1—2. Superior labials nine, fifth and sixth in orbit, last 

 two longer than high. Inferior labials 11, the anterior very wide ; postgeni- 

 als longer than pregenials. 



Scales in fifteen rows for a part of the length, in eleven, on the posterior 



1868.] 



