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FISHES OF THE FAMILY LORICARIID. 
a. First dorsal ray 3-3 the length of head. 
Interorbital width 23-22 times in the length of head; last dorsal 
ray, when laid back, reaching spine of adipose fin; caudal 
peduncle 2?-24 times aslong asdeep ...... . . 6. X.cirrhosaC. & V. 
Interorbital width 23 times in the length of head; last dorsal ray, 
when laid back, not reaching spine of adipose fin; caudal 
peduncle 2} times aslong asdeep. . . . . . . . . . 7%. X. chagresi Eigm. 
8. First dorsal ray 4-7 the length of head. 
Interorbital width 2} times in the length of head; last dorsal ray, 
when laid back, reaching spine of adipose fin ; caudal peduncle 
23-23 times aslongasdeep. ..... 2... =. . . 8. X. occidentalis Ren. 
c. Length of mandibular ramus 2-21 times in the interorbital width. Length of base 
of dorsal equal to its distance from spine of adipose fin, which is not reached by the 
last ray, when the latter is laid back. 
Diameter of eye 7} times in the length of head, interorbital width 
22 times, length of snout twice (in a specimen of 100 mm.) . 9. X. brevipinnis Rgn. 
Diameter of eye 10 times in the length of head, interorbital width 
3 times, length of snout 1? times (in a specimen of 100 mm.) . 10. X. montana Rgn. 
d. Length of mandibular ramus 14-1} times in the interorbital width. Length of base 
of dorsal equal to its distance from spine of adipose fin, which is not reached by the 
last ray, when the latter is laid back. 
Interoperculum armed with 12-16 spines ; pectoral spine extending 
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Interoperculum armed with 20-30 spines ; pectoral spine extending 
to, or nearly to middle of ventral . . . . . . . . . . 12. X. stigmatica Kigm. 
1. XENOCARA LATIFRONS. (Plate XV. fig. 1.) 
Chetostomus latifrons Giiuth. Proc. Zool. Soc. 1869, p. 426. 
Depth of body 5 times in the total length, length of head 24 times. Head 14 times 
as long as broad and 13 times as long as deep. Diameter of eye 64 times in the length 
of head, interorbital width 24 times, length of snout 1} times. Length of mandibular 
ramus 34 times in the interorbital width. Snout with a broad naked margin, without 
tentacles; interoperculum armed with 13-15 spines, the longest equal to 7 the length 
of head. Posterior scutes rather strongly spinate; none of the scutes carinate ; 
24 scutes in a longitudinal series, 6 between dorsal and adipose fin, 11 between anal 
and caudal. D. 1 8, the first ray equal to # the length of head; length of base of 
dorsal a little less than its distance from the caudal. A. I 4. Pectoral spine 
extending to middle of ventral. Caudal peduncle 23 times as long as deep. 
Olivaceous; a black spot at the base of the first interradial membrane of the dorsal. 
Total length 160 mm. 
One specimen from the Peruvian Amazon. 
