404 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



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without light margins. The first dorsal fin is light throughout ; the 

 second dorsal has a narrow light streak near its base, but the main 

 part of the fin is dusky, shading into black anteriorly; the anal is 

 dusky throughout. The dusky pectoral fin becomes lighter toward 

 the tip of the filamentous ray and blackish near the base of the fin. 

 The blackish ventral fin becomes lighter toward the inner margin of 

 its base. 



This species, together with G. multifilis, is readily distinguishable 

 "from denticulatus, colletti, and ?nagnifilis, differing from all in the 

 wider interorbital space and the wholly dark branchial cavity, from 

 denticulatus and colletti also in the coarser dentition, and from 

 magnifilis also in the shorter fin filaments. The number of pyloric 

 caeca seems also to be characteristic of the species ; there are 24 to 29 

 in magnifilis, 35 to 52 in introniger, 61 to 75 in denticulatus, and 95 

 in colletti. 



From G. multifilis, G. introniger differs in a number of diagnostic 

 characters: the gill-rakers are shorter, more widely spaced and 

 bluntly, instead of sharply, tipped, and they are fewer in numbe£, 

 there being 20 to 24 instead of 26 below the angle of the outer arch ; 

 the head is much firmer, the sensory channels being less developed ; 

 the teeth are considerably finer, and in wider bands, the premaxillary 

 band being contained 2.2 to 3.0 m the suborbital width, rather than 3.3 

 to 3.8 times ; the body is a little more robust, the depth in G. multi- 

 filis not equaling the length of the head to the angle of the preoper- 

 cular ridge ; the distance between the anus and the base of the ventral 

 is decidedly longer, being two-thirds instead of half as long as the 

 head; there are 7 instead of 6 scales above the lateral line; the 

 fin filaments are shorter, the dorsal spine and the outer ventral ray 

 being shorter, instead of longer, than twice the length of the head. 

 G. introniger differs in similar details from G. melanopterus of Ha- 

 waii, and from G. longifilis in the wider interorbital, wider bands of 

 teeth, and especially in the fewer gill-rakers (see measurements and 

 counts of G. longifilis in the table of measurements and counts of the 

 next species, G. multifilis). The number of pyloric caeca proves 

 valuable in distinguishing these species also ; 35 to 52 were counted in 

 G. introniger, 12 to 16 in G. multifilis, 15 in G. melanopterus, and 

 but 8 in G. longifilis. 



This species lives in water probably deeper, on the average, than 

 that inhabited by G. denticulatus. Its general appearance and struc- 

 ture is in harmony with such a difference in distribution. G. introni- 

 ger inhabits depths as great as those from which G. magnifilis Avas 

 dredged, but in much colder water. 



