FISHES OF THE FAMILY LORICARIIDA, 317 
from their base to the anal opening, or sometimes nearly to the anal opening. 
Adipose fin long, moderately developed, without trace of a spine. Distance from 
tip of snout to base of first dorsal ray 25 times in the total length, from base of last 
anal ray to caudal 61~7 times. Greyish ; caudal with some dark spots. 
Total length 88 mm, 
Ten specimens from Eastern Ecuador. 
18. ARGES PERUANUS. 
Arges peruanus Steind. Sitzb. Ak. Wien, lxxii. pt. i. 1875, p. 601, pl. ix. figs. 3-6, and Denkschr. 
Ak. Wien, xli. 1879, p. 173. 
Length of head 34-4 times in the total length. Interocular width less than the 
distance from eye to posterior nostril, 33-93% times in the length of head. Outer series 
of teeth of the premaxillaries compressed incisors, with the upper edge slightly 
emarginate, notched; mandibulary teeth similar; barbel extending % the distance 
from its base to the gill-opening. First dorsal ray equal to 3 the length of head ; 
pectoral spine extending to anterior 3 of ventral; ventrals originating below or slightly 
in advance of the first dorsal ray, extending }—3 of the distance from their base to the 
anal opening ; adipose fin long, low, feebly developed, without trace of spine. Distance 
from tip of snout to base of first dorsal ray 2} times in the total length, from the base 
of last ray of anal to caudal nearly 5 times. Uniform brownish ; fins without spots. 
Total length 63 mm. 
Four specimens from Amable Maria, Peru. 
19. ARGES SIMONSH, sp. n. (Plate XXI. fig. 9.) 
Length of head 4—4; times in the total length. Interocular width equal to the distauce 
from eye to posterior nostril, 3}-34 times in the length of head. Outer series of teeth 
of the premaxillaries incisors, with straight or notched edges; mandibulary teeth 
similar; barbel extending }-$ of the distance from its base to the gill-opening. First 
dorsal ray equal to 3—} the length of head; pectoral spine extending to anterior + of 
ventral ; ventrals originating below the first dorsal ray, extending 2-2 of the distance 
from their base to the anal opening; adipose fin long, low, moderately or well 
developed, without trace of spine. Distance from tip of snout to base of first dorsal 
ray 23-23 times in the total length, from base of last anal ray to caudal 54-6 times. 
Body sometimes spotted or marbled with dark brown ; some dark spots on the dorsal. 
Total length 80 mm. 
Five specimens from Huaras, Peru, 10,700 feet, collected by the late Mr. P. 
O. Simons. 
