488 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



including tlie largest specimen seen, which is 125 mm. long. The 

 material now available suggests that the species may not grow large. 



A specimen (U.S.N.M. No. 128122), 68 mm. (53 mm. to base of 

 caudal) long, from Sechura Bay, has been selected as the type. The 

 following proportions and enumerations are based on the type: 

 Head 2.65 in length; depth at base of pectoral about 3.8; width of 

 head at eyes 4.2; and pectoral 5.9. Eye in head 7.5; snout 1.95; 

 interorbital 6.4; caudal peduncle 7.2; longest dorsal ray 2.1; longest 

 anal ray 2.8; and longest pectoral ray 2.2. D. 8; A. 7; P. 15. 



The specimens in the collection of the U. S. National Museum, 

 which seem to be of this species, had been identified as S. annulatus 

 or as S. lobatus (Steindachner) . This species differs from annulatus 

 in having a longer and slenderer head ; in having nearly the entire body 

 covered with spinules, whereas they do not extend forward beyond the 

 interorbital or backward beyond the origin of dorsal in annulatus; 

 and in having only 14 or 15 rays in the pectoral fin, while annulatus 

 nearly always has 16. The light color markings described are much 

 less distinct, and generally at least the body is less profusely spotted 

 on the sides, and the pale margin of the caudal is much more conspicu- 

 ous than in annulatus. 



S. lobatus, to which some of the specimens of this species were 

 assigned by different workers, was originally described and figured 

 by Steindachner (1870, p. 18, pi. 5, fig. 3) as having no spinules on the 

 snout and not extending nearly to origin of dorsal; the interorbital 

 as narrow and concave; the profile as rising abruptly at the eyes; 

 and the nostrils probably with a broad flap and without an opening, 

 though owing to drying its exact nature could not be determined. 

 There is now at hand a specimen (U.S.N.M. No. 101075), 60 mm. 

 long, from the "west coast of Mexico," that has a nostril with a broad 

 flap, without an opening; a narrow concave mterorbital; with the 

 spiny area on the back ending before origin of dorsal, though it does 

 extend on the snout; and with 15 rays in the pectoral. This specimen, 

 then, apparently may be identified as lobatus, whereas most if not all 

 the examples, exclusive of the type, heretofore identified as this species 

 were incorrectly determined. Unless the nostril is abnormal in the 

 specimen now at hand, lobatus probably should be placed in a distinct 

 genus according to modern classification. Except for the peculiar 

 nostril, lobatus seems to be close to S. angusticeps (Jenyns) . 



S. sechurae apparently is nearest S. angusticeps, from which it 

 differs in having a shorter head and a broader interorbital that is not 

 concave; the dorsal profile does not ascend abruptly in front of eyes; 

 and although the extent of the spinules covering the body is not very 

 different in the young of the two species, S. angusticeps has flaps of 

 skin, varying greatly in number and position among specimens along 

 the side, and a rather constant pair at the shoulders, none of which are 



