IS'O-] ^^^ [Cope. 



Scales smooth, with one apical pore-pit. Anal plate and subcaudals 

 double. 



This genus has head-shields arranged like those of Bhegnops, Cope, 

 (Proc. Acad. Nat. Sci. Phil. 1866, 128), but the dentition is entirely dis- 

 tinct. It is nearer to Tantilla B. and G. but tli^at genus does not present 

 the edentidus characters, and exhibits a preoccular instead of a loreal 

 plate. The pupil is round. The general form is slender for a Calamari- 

 an serpent, and the tail is unusually elongate ; the head is not distinct. 



CJiar. Specificus. Scales in sixteen or seventeen rows. Labials 6-7, third 

 and fourth in orbit. Two postorbitals ; temporals, 1 — 2 — 3. Rostral 

 broad, crescent shaped ; internasals half as large as prefrontals. Frontal 

 nearly triangular, with apex behind ; anterior border strongly convex. 

 Superciliaries sub-triangular, with short apex anterior. Occipitals elon- 

 gate. Geneials one pair followed by a row of three scales. The tail 

 measures between one-third and one-fourth of the total length, nearer 

 one-third, but the only specimen now by me has the extremity mutilated. 

 Gastrosteges, 216. Length of a specimen, 0m.220 ; other larger ones are 

 not now before me. 



Color, mouse-color above, white below, a pale spot on each nasal plate, 

 and a dusky one on each side behind the rictus oris. From Chinandega, 

 in the Occidental department, Nicaragua, discovered by J. H. McNiel. 

 Several specimens were taken from a well, forty feet deep. 



This species in scutellation and form of head is related to the Calamar- 

 inse, and it is doubtless a borrower, but its scale pores and long tail are 

 exceptional features. 



CONTRIBUTION TO THE ICHTHYOLOGY OF THE MARAJNON. 



{Bead before the Amer. Phil. 8oc. Aug. 19 1870.) 



BY E. D. COPE, A. M. 



CHARACINID^E. 



Tetragonopterus orientalis, Cope. 



D. 11, A. 29 ; scales 7-37-8. The depth of the body one-half the length 

 (without caudal fin) ; the head one-fourth of the same. Dorsal fin above 

 a point a short distance behind the origin of the ventrals. Anterior anal 

 rays not elongate. Diameter one-third length of head, 1.5 times in the 

 convex interorbital width. The extremity . of the mandible extends a 

 little beyond the line of the anterior rim of the orbit. Pectoral extend- 

 ing a little beyond basis of ventrals. A broad silver band from upper 

 opening of operculum to caudal, with a black spot near each end. 

 Length 0.097 M. 



From Para. Mus. J. Carson Brevoort. 



Tetragonopterus stilbe. Cope. 



Depth contained 2.4 times in length (without caudal) ; length of head 

 3.5 times in the same. Radii, D. 11, A. 38, scales 8 — 39—10. Inter- 

 orbital width equal that of eye, and one-third length of head. Dorsal 



