new South-American Fishes. 623 
Piabucina pleurotenia. 
Depth of body 42-54 times in the total length, length of 
head 43-42 times. Snout as long as or longer than the eye, 
the diameter of which is 42-6 times in the length of head, 
interorbital width 23-22? times. Maxillary extending to 
below anterior 4 of eye ; mandibular rami well separated, the 
interspace somewhat narrowed anteriorly, but not tapering to 
a point. Sc. 30-32/8. D. II 8, its origin nearly equidistant 
from middle of eye and base of caudal. A II 9. Pectoral 
3-g the length of head. Ventrals extending less than 3 
the distance from their base to the origin of anal (in the 
adult) or 2 of that distance (in the young). Caudal bilobed. 
Candal peduncle 11-14 times as long as deep. A dark 
longitudinal stripe along the middle of the side, ending in a 
dark spot on the base of caudal. 
Total length 160 mm. 
Six specimens from Merida, Venezuela, 1600 metres, 
collected by Sr. Briceiio. 
This species differs from the preceding in the smaller eye, 
different position of the dorsal, coloration, &c. Both are 
distinguished from P. undteniata, Gthr., and P. elongata, 
Bler., by the broader interspace between the mandibular rami, 
aud from P. erythrinoides, C. & V., by the fewer scales. 
Trichomycterus vittatus. 
Length of head 63 times in the total length. Head as 
broad as long. Diameter of eye 2} times in the interocular 
width, which is 3} times in the length of head. Snout 
slightly shorter than the postorbital part of head. Barbels 
equal to # the length of head. Dorsal with 6 branched rays, 
originating in advance of the anal opening, the distance from 
its point of origin to the caudal 1} times in the distance from 
the former to the tip of snout. Anal with 4 branched rays, 
originating slightly behind the vertical from the last dorsal 
ray, the distance from the base of its last ray to the caudal 44 
times in the total length. Longest branched ray of pectoral 
2 the length of the simple outer ray, which is as long as the 
fe Ventrals extending # of the distance from their base 
to the origin of anal. Caudal truncate. Head and body 
with dark spots; a dark longitudinal stripe along the middle 
of the side. 
Total length 78 mm. 
One specimen from the Marcapata Valley, E. Peru, 
collected by Mr. Ockenden. 
Allied to 1. Knert, Stdr., which has the head longer than 
broad and the caudal emarginate. 
