122 BULLETIN 95, UNITED STATES NATIONAL MUSEUM. 



a single flat spine, above which in the upper angle are two others, 

 indistinct. 



Spinous dorsal low, upper outline sinuous, fifth spine longest, 2.7 

 in head; soft dorsal much higher, acute, the posterior rays shorter 

 than the anterior, longest ray 1.44; caudal deeply forked, the lobes 

 large and round, of which the upper is considerably longer, equal to 

 length of head; anal spines small, the second the longer, 3 in head, 

 middle rays of anal longest, 1.7 in head; depth of caudal peduncle 

 1.88; ventrals moderate, reaching to behind anus, 1.16; pectoral 

 broad, upper rays longest, 1.09 in head ; scales large, regular, densely 

 covering body and head except snout in front of eyes, area around 

 mouth, and lower margin of preopercle ; scales along middle of side 

 largest, most of them with accessory scale at base, those above lateral 

 line most numerous; fins densely scaled, those on spinous dorsal 

 concealing all but tips of spines. 



Coloration in life: Back and sides a very dark brownish olive, each 

 scale with a very dark margin, lighter centrally; a bright bar of 

 dusky gold extending incompletely across body a short distance 

 before anterior end of anal; fleshy flaps margining opercle very 

 dark; soft parts of fins black; throat and lower parts of head a light 

 chestnut brown. Description based on a specimen (field No. 509) 

 20.3 cm. long, from Mollendo. 



Color in life of a specimen (field No. 09172) 14.6 cm. long, from 

 Guanape North Island, general color dark olive green, lightened by 

 the golden bar and the metallic greenish centers of the scales, the 

 greenish centers giving place in some parts, especially anteriorly, to 

 bluish or violet ; lower part of head and throat tinted purple. 



In alcohol, the individuals from Guanape and Lobos de Afuera 

 are much darker (almost a bluish black) than the one from Mol- 

 lendo, the latter having a decided brownish cast. 



The three small examples (No. 278) taken in a tidal pool in the 

 rocks were in life brilliant blue in color; in the water, the general 

 color of darker blue varied by shining spots of lighter blue. They 

 have D. XIII, 18 or 19; A. II, 14; scales 4-28-12; preopercle 

 strongly serrate; top of head and region around mouth to below 

 anterior margin of pupil without scales. 



From a study of the young it is evident that the genus Nexilosus 

 is very close to Pomacentrus^ differing in the adnate condition of 

 the suborbital, a condition which appears to be approached by some 

 of the young of this genus. 



The only previous records of this species are those of Tschudi 

 who obtained a few examples, 9 inches long, from Huacho, Peru; 

 two large examples, 21.9 and 22.6 cm. long obtained by Doctor Plate 

 at Cavancha Bai near Iquique and described by Steindachner, and 

 several specimens obtained by Heller and Snodgrass at Tagus 



