ANNOTATED LIST OF THE SPECIES 193 
the adipose spine; caudal fin obliquely truncate; ventrals reaching the middle of 
the anal or farther; pectorals to or beyond the origin of the second third of the 
ventrals, base of dorsal equal to its distance from a point halfway between the 
caudal and the tip of the adipose spine. 
Head and sides everywhere with many obscure black spots, smallest of the 
head, those of the caudal peduncle about the size of the pupil; lower surface of 
caudal peduncle similarly spotted, the belly unspotted; a series of spots between the 
dorsal spine and the first ray; two series of spots between the rays, the spots con- 
spicuous, of the size of those on the center of the caudal peduncle; each membrane 
of the caudal, anal, pectoral, and ventral fins with a dark longitudinal line bordered 
by hyaline; tips of the upper and lower caudal lobes rusty. 
In the smaller specimen the peculiar markings of body and fins have not de- 
veloped; the caudal is obliquely truncate, blackish, margined with rusty, the rusty 
widest on the tips of the lobes. 
Near to C. anomalus in the size of the eye, length of mandibular ramus, form 
of the caudal peduncle, depth (2.14 in length), the number of the dorsal rays, and 
the narrow interorbital; differing in the number of anal rays, more slender form 
(head in the length about 3.6 compared with 3), and in the coloration, especially 
that of the fins. 
182. CHAETOSTOMA MARMORESCENS Eigenmann and Allen, sp. nov. 
15408, many, 52-135 mm., the largest the type, Huancachupa creek, near Hudnuco, elevation 6000 
feet, Allen, October, 1918. 
15402, 3, 86-107 mm., Rio Tingo, Hudnuco, Allen, October, 1918. 
Evidently allied to loborhynchus, anomalus, and taczanowskii, resembling the 
last-named in respect to the form of the dorsal fin, the second-named in the propor- 
tions of the eye and interorbital space and slender caudal peduncle; differing from 
anomalus in the longer, lower form of the dorsal fin, and from all in the warty 
growths of the head. 
Head 3.0-3.9; depth 5.25-5.75; D. I, 7 in two, I, 8 in 68, and I, 9 in 18; A. I, 
3 or I, 4; scutes 25 + 1, 5 or 6 scutes between the dorsals, one or two of them un- 
paired, 9 or 10 between anal and caudal; base of dorsal nearly equal to its distance 
from the caudal; naked part of snout densely covered with warts a little larger than 
those on the lip; interopercle with 8-16 nearly or quite straight spines. 
Eye 8 in snout, 2.5 in the postorbital part of the head, 3.4 in interorbital; 
interorbital 3.25—3.56 in the length of the head; loreal region with the naked portion 
wider than the armored part; mandibular ramus equals interorbital; head but little 
longer than wide. 
Dorsal much longer than high, the last ray sometimes reaching adipose; adipose 
well developed; caudal very slightly emarginate in the young, oblique and slightly 
rounded in the adult; ventrals rounded or angulated, the fourth ray forming the 
angle, reaching the middle of the anal; pectoral spine reaching a little beyond origin 
of ventral, the first ray reaching beyond the spine; depth of caudal peduncle 2.25— 
2.5 in its length. 
