NATURAL SCIENCES OP rillLADELnil A. 67 



rostral opens in a ningh plate, tliere is but one post-ocular, tlic parietals are 

 long, the eye rests on the third and fourtli sui)ra-labials, and the shajic of the 

 scales is very dillerent, being lanceolate and not long and quadrangular; the 

 internasals arc smaller in proportion, the rostral docs not extend so far back- 

 ward on tlie top of the head, and the frontal differs in shape ; it approaches 

 more nearly Leptophis (Syncrateriau), a genus also existing on the AV'cst Coast 

 of Africa, but in Leptophis, the internasals are proportionately /ar^cr, the frontal 

 more acute posteriorly, the rostral quite different in shape, the frenal long and 

 narrow, but two post-oculars, the eye resting on the iifth and sixth supra-labials, 

 the latter plate being much prolonged at its posterior and superior angle, and 

 the posterior gencials, or intermediate sub-niaxillary plates, are longer than the 

 anterior and more narrow. In Bucephalus the scutes beneath the tail are bifid 

 for one-fourth of its lengtli, simple in the remainder, and the posterior teeth are 

 channelled (Opistoglyph) ; atc propose therefore for this remarkable Arboricole 

 (Jphidian the generic name 



T1IRAS0PS.» 



Gen. Char. Head long, flat above, somewhat ti'uncate anteriorly ; shelving in 

 front ; rostral extending upon the top of the head ; internasals of about same 

 length as pre-frontals ; frontal three and a half lines in length, and about as 

 broad anteriorly, rounded posteriorly ; parietals short and broad, nostril be- 

 tween two plates ; a quadrangular frenal ; one antocular, three post-oculars ; 

 e^'e resting on the fourtli and fifth supra-labials; pupil circular ; j)OSterior 

 geneials broader than the anterior; teeth of the upper maxillaries Syncratorib,n, 

 the posterior twice as long as the anterior, not channelled, but trenchant, the 

 preceding ones sharp pointed, a wide space in front destitute of teeth ; pterygo- 

 palatine teeth small, in two nearly' parallel rows ; mandibular teeth presenting 

 no larger or longer ones anteriorly, the posterior ones a little shorter ; neck 

 nearly as broad as jjosterior part of head, body long, rather stout in the middle, 

 covered with long and quadrangular imbricated and carinated scales of about 

 equal breadth except those of inferior row which are broader and shorter than 

 the others ; scales and scutes presenting a silken appearance ; abdomen angular 

 but not distinctly so, the gastrostega ascending obliquely upon the flanks ; tail 

 long, sub-caudal scutes bifid. 



Thrasops flavigclaris, nob. 



Sp. Char. 13 rows of scales ; jet black black above with a silken lustre, 

 mingled with brown upon the head ; lips dove color ; chin and throat white, or 

 light yellow ; neck white or light yellow, black spotted ; abdomen and under 

 part of tail black or yellowish ; length 5 ft. 10|- inch. (Fr.) 



Habitat. Gaboon ; two specimens in Mus. Acad. N. S. one presented by Dr. 

 Henry A. Ford, the other by Mr. DuChaillu. 



Gen. Remarks. The description in the 4th vol. of the Proceedings is quite ac- 

 curate, and characterizes this serpent well, except its dentition. Its jet black and 

 silken lustre, and large and somewhat impudent eyes, make, we should think, 

 this reptile one of the most remarkable among the Arboricole Ophidians so 

 numerous in Western Africa. 



CoroneUa trianyularis, nob. Proceed. Acad. N. S. vol. vii. p. 140. 



Coluber Icevis, Proceed. A. N. S. Vol. ii. p. 118. This serpent described under 

 the above names, is not a CoroneUa, but belongs to a new genus of Syncrate- 

 rians, for which we propose the name 



HETERONOTUS. 



Gen. Char. Dentition of CoroneUa. Head long, temples somewhat swollen, 

 eyes of moderate size, nostrils latero-superior between two plates; a short frenal; 

 one pre-ocular; two post-oculars ; eight superior labials, the eye resting on the 

 fourth only; a broad rostral; two internasals rather long ; two broad pre-fron- 



*@f>a<ro(, audax, and ^, oculus. 



1857.1 



