FISHES OF THE FAMILY LORICARIIDA. 297 
Length of head 33-3} times in the total length. Head 1% times as long as broad. 
Diameter of eye 7-9 times in the length of head, interorbital width about 5 times, 
length of snout about 14 times. Supraoccipital with a pair of weak keels ; orbit with 
a large rounded notch; snout with a long narrow process, expanded and armed with 
recurved spines at the tip. Lips and teeth as in the preceding species. 27 scutes in 
a longitudinal series, 11-13+414-16; lateral keels separate throughout, strong; all 
the scutes in front of the dorsal weakly carinate; lower surface of head naked; 
abdomen covered with a few large plates. Fins as in the preceding species. Body 
with 6 dark cross-bands ; caudal with blackish spots. 
Total length 122 mm. 
R. Amazon. 
13. OXYLORICARIA. 
—Sturisoma (nomen hybridum) Swainson, Nat. Hist. Fishes, i. p. 8337 (1838). 
Oxyloricaria Bleek. Ned. Tijd. Dierk. i. 1863, p. 80. 
Harttia Steind. Sitzb. Ak. Wien, Ixxiv. 1876, pt. i. p. 668; Higenm. & Eigenm. Occ. Pap. Cal. Ac. 
i. 1890, p. 385. 
This genus is distinguished from Loricaria by the numerous and setiform teeth and 
the absence of an orbital notch. In many of the species also the snout has an anterior 
projection. Vertebre 5+7-++25 (in O. lyra). Ribs present, slender. 
Rivers of S. America. 
In all the species the head has no ridges or prominences, and is evenly convex 
above ; the lips are papillose, the lower rounded and with short marginal fringes ; the 
barbel is short. In the species with a rostrum the sides of the head are armed with 
bristles in the males. 
It seems most convenient to recognise this genus with the present limits. A sub- 
division based on the presence or absence of a rostrum would result in separating 
O. brevirostris from O. guentheri, to which it seems to be at least as closely allied as to 
O. platystoma. 
Key to the Species. 
I. Snout rounded or pointed, not produced as a rostrum. 
Abdomen naked, except for the lateral series of plates and a pair of 
analgplates; |i ts Uncen aC 3) co so -) ae Pm LemON Vontcaneonmes Sud: 
Abdomen covered with numerous small plates, arranged in 8-10 irre- 
; gular series between the lateral series; a pair of anal plates . . 2. O. platystoma Gthr. 
Abdomen covered with plates, arranged in 3 series between the lateral 
SenCSMET rc? = OEP eee Ss 5) es poienct ed eure On Onerirosinis: Wigton 
II. Snout produced, forming a distinct rostrum. 
A. Pectoral spine extending nearly to base of ventral or a little beyond. 
Length of snout 14 times in that of the head, diameter of eye 7 times 
y) 
2R2 
