418 



BULLETIN OF THE BUREAU OP FISHERIES 



laries usually are half as wide as long and make an angle of 45° to 60° with the hori- 

 zontal axis of the head. Instead of a smooth curve connecting the tip of the snout 

 with the occiput, as in the longjaw, where the premaxillaries occupy a similar position, 

 the profile in the blackfin runs straight from the tip of the premaxillaries to their 

 articulation with the rostroethmoidal cartilage and then continues in a faint curve to 

 the occiput. The maxillary is pigmented and seldom extends much beyond the 

 anterior edge of the pupil. The snout, viewed from the side, is deep and blunt and is 

 contained 3.5-3.9 (4.1) times in the head length. The eye is large and is contained 

 4-4.4 (4.6) times in the total length of the head. The lower jaw usually is pigmented 

 conspicuously and equal to or somewhat longer than the upper; occasionally, however, 

 it is somewhat shorter. The gill rakers on the first branchial arch number (15) 

 16-19 + (26) 29-32 (34) = (41) 46-50 (52). Scales in the lateral line number (74) 

 80-87 (89). Scale rows around the body just in front of the dorsal and ventrals 

 number (41) 42-44 (45); 79 just in front of the adipose and anus (32) 33-35 (36); 7B 

 around the caudal peduncle (23) 24-26 (27). 79 Dorsal rays are 10-11; 79 anal rays 

 (10) 11-12 (13); 79 ventral rays 11-12; 79 and pectoral rays (15) 16-17 (18). 89 The 

 length of the pectoral fin is contained (1.5) 1.6-1.8 (2.2) times in the distance from the 

 pectorals to the ventrals. 



The distal half of the dorsal margin of the pectorals is usually decurved. The 

 ventrals are contained 1.2-1.5 (1.6) times in the distance from their origin to that 

 of the anal. 



COLOR IN LIFE 



The general tone is silvery, as in other Leucichthys, but in typical specimens the 

 silvery cast is least conspicuous in this species on account of the heavy pigmentation. 

 The entire dorsal surface is blue black, almost obscuring the pea green to blue green 

 beneath. Below the lateral line a pale blue green is evident beneath the silvery layer. 

 The sides and cheeks are suffused with a purplish iridescence, which is strongest above 

 the lateral line. The maxillary and mandible are whitish, both more or less heavily 

 pigmented. The fins also are whitish, all of them usually so heavily pigmented that 

 the effect is also blue black. 



In spirits the entire dorsal surface is more or less heavily pigmented, varying from 

 dense pigment, giving an almost black effect in some individuals, to but scattered 

 pigment in others. The top of the head is usually darker than the back, with the 

 pigment here often concentrated in front of the nares. The tip of the mandible is 

 dark, and the pigment of the back usually descends onto the sides of the head and 

 body, sometimes with undiminished intensity on the operculum, postoculars, and in 

 the preorbital area. The cranial margin and distal half of the dorsal fin, dorsal 

 margin and distal half of the pectorals, distal half of the ventrals, distal half of the 

 longer rays of the anal, and the lateral border and a broad band of the caudal are washed 

 more or less with intense black. More or less of the fins may be pigmented, but the 

 usual extent of the pigmentation has been given. 



No blackfins were collected during the spawning season, but a male in the Field 

 Museum collection, taken off Chicago, showed traces of pearls} and no doubt the 

 males, at least, develop pearl organs, as do all other members of the genus in the 

 basin. 



7( Sixteen specimens. 



!0 Twenty-six specimens. 



