FISHES OF THE FAMILY LORICARIID.F. 267 



1. OtOCINCLUS AFFINIS. 



Otocinclus affinis Steind, Sitzb. Ak. Wien, lxxvi. pt. 1, 1877, p. 221, pi. ii. fig. 1 ; Eigenra. & 

 Eigenm. Proc. Cal. Ac. (2) ii. 1889, p. 41, and Occ. Pap. Cal. Ac. i. 1890, p. 392. 



Depth of body 4f 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 2\ 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. I 7 ; origin of dorsal above or slightly behind that of ventrals. A. I 5. Pectoral 

 spine extending a little beyond base of ventral. Caudal emarginate. Caudal peduncle 

 2-g- 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 0. 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 0. affinis in his account of the Ternetz 

 collection. 



3. f Otocinclus vestitus. 



Otocinclus vestitus Cope, Proc. Ac. Philad. 1871, p. 283, pi. iv. fig. 2. 



Similar in most respects to 0. vittatus, from which it differs in the larger eye 

 (diameter about 3f 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 Eiver, E. Ecuador. 



4s. f Otocinclus flexilis. 



Otocinclus flexilis Cope, Proc. Am. Phil. Soc. xxxiii. 1894, p. 97, pi. vii. fig. 13. 

 Otocinclus fimbriatus Cope, t. c. p. 98, pi. ix. fig. 16. 



Very closely allied to the two preceding species. Diameter of eye 4^—5^ times in 



