550 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



oral length is one-third the postorbital. There are no enlarged 

 median nor lateral rostral tubercles. The large orbit is slightly 

 oval in outline; its length, greater than that of the snout, is con- 

 tained 3.22 (2.9 to 3.4 in 14 paratypes) times in the head, 1.4 times 

 in the postorbital. The least width of the flat interorbital space is 

 contained 1.2 times in the orbit, or 1.8 times in the postorbital; the 

 interorbital is narrower than in the closely related Japanese species, 

 as the following figures indicate : 



Table to show least width of interorbital space in hundredths of length to anus. 



The ridge and the margin of the preopercle extend downward and 

 backward, but are not sharply produced backward behind their gen- 

 eral courses at their angle. The suborbital width is narrower than 

 the pupil. The mouth is very large and a little oblique; the length 

 of the upper jaw, which extends backward a little farther than the 

 orbit, is contained 2.3 times in the head. The rather coarse teeth 

 are arranged in narrow bands on the jaws; the outer premaxillary 

 series is enlarged. The barbel is long and slender, being nearly as 

 long as the snout in the type, but usually decidedly longer in the 

 parat3 7 pes; its free length is contained about four times 1 in the head, 

 but varies in the paratypes as indicated in the following table : 



Table showing the length of the barbel in V. divergens as measured into the 



head. 



Length of barbel 2.8 2.9 3-0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 



Number of specimens 5 113 5 11 __ 1 1 



1 1 



The sensory canal system of the head is well developed, much as 

 in Hyme?iocephalus, but the membranous roofs over the canals are 

 thicker and are covered by firm scales, and the bony septa supporting 

 these membranes are stronger. The branchial aperture is extended 

 forward to below the hind margin of the orbit. The 13 to 15 short, 

 spinous gill-rakers are better developed than usual in the Coryphaen- 

 oidinae. but are not so numerous as usual in the species of Hj/nwn- 

 ocephalus. Seven branchiostegals. 



The scales, which are beset with numerous fine spinules arranged 

 in quincunx order, are more numerous than in V. gatynani, which 



1 Possibly when shortest the barbel has been injured some time during the life of the 

 individual. 



