FISHES OF THE FAMILY LORICARIIDA. 219 
side. Lower surface of head and abdomen entirely covered with small granular 
scales. D.I 7, the first ray nearly as long as the head, the last 3 as long; length of 
base of dorsal equal to the length of head. No trace of an adipose fin. A.I 5. 
Pectoral spine not reaching ventral. Caudal strongly and obliquely emarginate, 
Caudal peduncle 2% times as long as deep. Brownish; a few dark spots on the 
membrane of the dorsal, 
Total length 225 mm. 
One specimen, in the Paris Museum, from the Upper Amazon. 
24. +PLECOSTOMUS GENIBARBIS. 
Rinelepis genibarbis Cuv. & Val. Hist. Nat. Poiss. xv. p. 484, pl. 453 (1840). 
Acanthicus genibarbis Giinth. Cat. Fish. v. p. 253 (1864). 
Rhinelepis agassizii Steind. Sitzb. Ak. Wien, lxxvi. 1878, p. 228; Denkschr. Ak. Wien, xlvi. 1882, 
p- 7; Higenm. & Eigenm. Proc. Cal. Ac. (2) 11. 1889, p. 42, and Occ. Pap. Cal. Ac. i. 1890, 
p- 416. 
Length of head 5-3) times in the total length. Head 1-1} times as long as broad 
and 12-13 times as long as deep. Diameter of eye 6-8 times in the length of head, 
interorbital width 2—22 times, length of snout about twice. Scutes carinate, 22—25 in 
a longitudinal series. Brown, fins dark-spotted. In other characters essentially 
similar to P. pellegrini. 
R. Amazon. 
Cuvier and Valenciennes’ type was a stuffed specimen of 375 mm. The specimens 
described by Steindachner measure up to 280 mm. in total length. I am convinced 
that R. agassizii must be identical with #. genibarbis, as the descriptions agree very 
closely, and the differences are of little importance, the most striking being the more 
elevated dorsal fin of R. agassizii, due in some degree to the smaller size of the 
specimens, and probably also to the fin being broken in Valenciennes’ type, a condition 
which this author was very prone to overlook or neglect. 
25. PLECOSTOMUS PARAHYBA. 
Rhinelepis parahybe Steind. Sitzb, Ak. Wien, Ixxvi. 1878, p. 218, pl. ii.; Eigenm. & Eigenm. 
Proc. Cal. Ac. (2) ii. 1889, p. 42, and Occ. Pap. Cal. Ac. i. 1890, p. 415. 
Depth of body about 6 times in the total length, length of head 3-34 times, Head 
11-11 times as long as broad and twice as long as deep, Diameter of eye 7 times in 
the length of head, interorbital width 23-25 times, length of snout 1{-1} times. 
Length of mandibular ramus 25 times in the interorbital width. Snout obtuse ; 
supraoccipital with low median ridge; opercular plate rather large. Scutes not 
carinate, 25-26 in a longitudinal series, 11 between anal and caudal; a group of 
small granular plates behind the lower part of the temporal plate; supraoccipital 
bordered posteriorly by a pair of scutes, which nearly or quite exclude the first 
