FISHES OF THE FAMILY LORICARIIDA, 267 
1. OrocincLUs AFFINIS. 
Otocinclus affinis Steind. Sitzb. Ak. Wien, Ixxvi. pt. 1, 1877, p. 221, pl. ii. fig. 1; Eigenm. & 
Eigenm. Proc. Cal. Ac. (2) ii, 1889, p. 41, and Oce. Pap. Cal. Ac. i. 1890, 3 392. 
Depth of body 42 times in the total length, length of head 3 times. Diameter of 
eye 4} times in the length of head, interorbital width twice, length of snout 24 times. 
Supraoccipital with median ridge, ending posteriorly in an elevated triangular process. 
Scutes spinulose, not carinate, 24 in a longitudinal series. Lower surface of head with 
a naked area in front of the clavicles; abdomen covered with 3 series of plates. 
D. 17; origin of dorsal above or slightly behind that of ventrals. A.15. Pectoral 
spine extending a little beyond base of ventral. Caudal emarginate. Caudal peduncle 
23 times as long as deep. Olivaceous; a narrow dark stripe from eye to base of 
caudal; fins immaculate. 
Total length 40 mm. 
One specimen from Santa Cruz, South-eastern Brazil. 
2. OTOCINCLUS VITTATUS, sp. n. (Plate XV. fig. 3.) 
Closely allied to O. affinis. Depth of body 5 times in the total length. Supra- 
occipital without median ridge, not strongly elevated posteriorly, the dorsal profile 
rising evenly from snout to origin of dorsal. 21-22 scutes in a longitudinal series. 
A dark stripe from snout through the eye to the end of the middle caudal rays; caudal 
also with some dark spots which may form 2 or 3 vertical bars. In other characters 
similar to the preceding species. 
Total length 35 mm. 
Five specimens from Descalvados, Matto Grosso, Paraguay System, collected by 
Dr. Ternetz, referred by Boulenger to O. affinis in his account of the Ternetz 
collection. 
3. TOTOCINCLUS VESTITUS. 
Otocinclus vestitus Cope, Proc. Ac. Philad. 1871, p. 283, pl. iv. fig. 2. 
Similar in most respects to O. vittatus, from which it differs in the larger eye 
(diameter about 33 times in the length of head in a specimen of 40 mm.). A narrow 
dark stripe along the middle of the side in the posterior half of the body, expanding 
into a large black spot on the middle caudal rays. 
Ambyiacu River, KE. Ecuador. 
4, fOTOCINCLUS FLEXILIS. 
Otocinclus flexilis Cope, Proc. Am. Phil. Soc. xxxiii. 1894, p. 97, pl. vii. fig. 13. 
Otocinclus fimbriatus Cope, t. c. p. 98, pl. 1x. fig. 16. 
Very closely allied to the two preceding species. Diameter of eye 41-51 times in 
