THE SHORE FISHES OF PERU 235 



but they are more numerous, there being four or five, and they are 

 notably narrower than in X. rupestris. 



X. agassizi Steindachner (1875b, p. 6), which seems to be fairly 

 common in the Galdpagos Islands, differs in having even smaller 

 scales than X. rupestris, though the scales anteriorly above the lateral 

 line are less reduced, and the rows are less strongly oblique (10 or 

 11-68 to 73 in 8 specimens). The scales, furthermore, are less 

 strongly serrate, being in fact rather definitely cycloid above lateral 

 line in advance of dorsal; and the pectoral is notably longer than in 

 either of the species herein compared, being falcate, and reaching far 

 beyond tips of ventrals, to origin of anal in the larger specimens, 

 25 to 30 percent of length. The eye is larger than in X. rupestris, 

 10.3 to 12.0 percent of length. No caudal spot and no dark longitu- 

 dinal lines or bands are evident in the specimens at hand. 



Range. — Known only from the type material from Lobos de Afuera 



Bay, Peru. 



Genus XENISTIUS Jordan and Gilbert, 1883 



Body rather elongate, moderately compressed; head fairly low, 

 pointed; eye moderately large; mouth oblique; lower jaw projecting; 

 teeth mmute, in a narrow band on each jaw and on vomer; margin of 

 preopercle rather strongly serrate; scales moderate or rather small, 

 ctenoid; dorsal fin nearly or quite continuous, with 12 or 13 rather 

 slender spines, and 13 to 15 soft rays, the soft portion notably longer 

 than the spinous part; anal with 3 spines and 11 to 13 soft rays. 



A single species is included in the Peruvian collections studied. 

 The genus apparently has not been reported from any locality inter- 

 mediate of the Gulf of California and northern Peru. 



XENISTIUS PERUANUS. new species 



Figure 51 



Xew'stius californiensis Nichols and Mtjrpht (not of Steindachner), 1922, p. 509, 

 Lobos de Tierra Island, and North Chincha Island, Peru ("several hundred 

 young" reported). 



Head 2.8 to 2.9; depth 3.4 to 3.8; D. XIII, 13 to 15; A. Ill, 11 to 

 13; P. 17 or 18; scales 70 to 80. 



Body fairly compressed, its greatest thickness about half its depth; 

 back moderately elevated; profile nearly straight from nostrils to 

 nape; ventral outline anteriorly more strongly rounded than dorsal 

 outline; head large, compressed; caudal peduncle slender, 4.0 to 4.4 

 in head; snout moderately pointed, 4.0 to 4.7; eye 3.1 to 3.7; inter- 

 orbital 5.3 to 6.2; mouth oblique; lower jaw projecting; maxillary 

 reaching somewhat beyond front of eye, 3.2 to 3.5 in head; teeth 

 minute, a narrow band in each jaw, and in a V-shaped band on vomer; 

 gill rakers slender, those at angle fully half length of eye, 21 or 22 on 

 lower and 9 to 11 on upper limb of first arch; scales small, strongly 



