FISHES OF THE FAMILY LORICARIIDA, 265 
4. HYPopropoMA JoBERTI. 
Hypoptopoma bilobatum (non Cope) Steind. Denkschr. Ak. Wien, xli. 1879, p, 45, pl. v. fig. 2. 
Otocinelus joberti Vaill. Bull. Soc. Philom. (7) iv. 1880, p. 147. 
Length of head 23 times in the total length. Diameter of eye 5} times in the length 
of head, interorbital width 13 times. 23-24 scutes in a longitudinal series ; adipose fin 
present, feeble ; in other characters similar to the preceding species. 
Total length 78 mm. 
A single specimen: Upper Amazon; R. Jurua. 
After examination of the type of 0. Joberti I am fairly certain of its specific identity 
with the specimen figured by Steindachner as H. bilobatum. 
&. TH YPOPTOPOMA STEINDACHNERL. 
Hypoptopoma thoracatum Steind, Denkschr. Ak. Wien, xli. 1879, p. 47, pl. vi. fig. 1; Higenm. 
& Eigenm. Proc. Cal. Ac. (2) ii, 1889, p. 40, and Occ. Pap. Cal. Ac. i. 1890, p. 389. 
Hypoptopoma steindachneri Bouleng. Proc, Zool. Soc. 1895, p. 527. 
This species, as described and figured by Steindachner, seems to differ from the 
preceding in the shorter body (depth 5 times in its length; caudal peduncle 24 times 
as long as deep), longer pectoral spine (extending to the first anal ray), and in the 
absence of spots on the fins. 
The specimen figured, from the Rio Negro, is 78 mm. in total length. 
6. PHYPOPTOPOMA GULARE. 
Hypoptopoma gulare Cope, Proc. Am. Phil. Soc. xvii. 1878, p. 679. 
Very closely allied to the two preceding species, differing apparently in having a 
single plate in front of the clavicles instead of a transverse series of 4. Dorsal brown 
at the base, with some dark spots on its middle. Caudal brownish, with a light 
margin. 
Maranon, Upper Amazon. 
10. Ovoctncuus. 
Otocinclus Cope, Proc. Ac. Philad. 1871, p. 283; Eigenm. & Eigenm. Proc. Cal. Ac. (2) ii. 1889, 
p- 41, and Oce. Pap. Cal. Ac. i. 1890, p. 392. 
Hisonotus Eigenm. & Higenm. Proe. Cal. Ae. (2) ii. 1889, p. 40, and Occ. Pap. Cal. Ac. i. 1890, 
p. 390. 
Parotocinclus Kigenm. & Eigenm. t. c. p. 41, and t. c. p. 392. 
Microlepidogaster Eigenm. & Higenm. t. c. p. 42, and t. c. p. 894, 
This genus differs from the preceding in the structure of the temporal plate, which 
is perforated like a sieve ; there is also an enlarged foramen at the posterior margin of 
the temporal plate and another in the axil of the pectoral spine. Eyes placed rather 
low or moderately high. Dorsal above or behind the ventrals, with I 7 rays, anal 
2N 2 
