1877." 47 {Cope. 
M. 
Seat lep Wee ea Nay ts oh ac on 1d "a Ra's ava !a\e Ale Sin iernyelaterpies Biaiardtsi crete 290 
ene teremd) OF Operculwm se eli va’ Neistoclenie oe siasees 042 
4 See Ve WUE (UTI Acre yordiale ticles eroiatesissaretete maratare ofc aiitte<k oO 
es SPeVEMItiess si she sdgoubowone SGC SL OL OpROOe - 151 
eG eM CLO TseU UM LUNe cee, vcare) sko ora. cisieiacererebeerctaey tetteretetetetel are 160 
ee mn cATN Ga ee imu lca vt sus, st atereteiater shal state ape etactla rots Sverre 170 
a 20 GUUOEN WO SER onaot Gd dfsnooounavaesAonodhae 250 
This species resembles the light varieties of the 7. dispar, but differs in 
the more posterior position of the @orsal fin, and the smaller number of its 
radii. 
No. 91, large specimen from Tinta 
I give the above description of a species probably named by Cuvier and 
Valenciennes, but no one can ascertain from their writings whether this is 
the case or not. 
41. TRICHOMYCTERUS POEYANUS Cope, sp. nov. TVrichomycterus rivulatus 
‘*Cuv. Val.’’ Cope, Proceed. Academy, Philada. 1874, p. 182. 
This species, formerly identified by me as above, I now name, dedicating 
it to my friend Prof. Felipe Poey of Havana. 
42. ARGES SABALO Cuyv. Val. XV, p. 335. Nos. 62-6 and 115 and 123, 
from the Rio Urubamba, at an altitude of 10,000 feet. 
43. OPHICHTHYS UNISERIALIS, sp. nov. 
Maxillary and mandibular teeth acute, in two series ; premaxillary and 
vomerine teeth in single series; no distinct canine teeth, the premax- 
illaries the largest. Cleft of the mouth moderate, -two-fifths the length of 
the head, which is one-half that of the body. Muzzle slightly projecting 
more than twice as long as the diameter of the eye. Body less than half 
as long as the tail. Pectoral fin a little more than one-third the length of 
the head, the dorsal originating nearly above its posterior sixth. Free 
portion of the tail very short ; the terminal inch of both dorsal and anal 
fins enclosed in a deep groove between two vertical dermal lamine. 
Length M. 0.330. 
Color above dark brown, below a little paler, the two colors separated by 
a water line. Along the lower border of the dark brown is a series of 
small yellowish spots a half inch apart, which are invisible on the posterior 
half of the length. 
From Peru, probably Pacasmayo. 
A species allied to the O. parilis and O. dicellurus of Richardson. 
44, MUSTELUS MENTO, sp. nov. 
Snout elongate, the length anterior to the mouth, exceeding the width 
between the external borders of the anterior nostrils, and considerably 
greater than the length between the angles of the mouth, external measure- 
ment. Anterior base of the anterior dorsal fin above the middle of the 
inner border of the pectoral fin ; the extremity of posterior portion reach- 
