gilbekt: the lantern-fishes of japan 73 



3. Dasyscopelus spinosus (Steindachner). 

 Scopelus spinosus Steindachner, Ichth. Notiz. V, 1867, p. 11, PL III, fig. 4 



(China). 



A few specimens were secured by the "Albatross" at the surface at Station 

 4921, south of Kagoshima (30° 23' 30" N., 129° 36' 30" E.). They are some- 

 what slenderer than Hawaiian specimens, and have the line of the supra- 

 anals noticeably more oblique, the anterior of the series being above the inter- 

 space between third and fourth ventrals, instead of vertically above the fourth 

 ventral as in Hawaiian material. At a Station in the South Pacific (16° 39' S., 

 149° 11' W.), the "Albatross" secured in 1899 nine specimens, of which five are 

 of the slender type with oblique supra-anals, and four of the deeper form with steep 

 line of supra-anals. There is no transition between the two, and although the 

 differences are of small magnitude, they merit attention and should be noted in 

 future collections from the Pacific. 



The number of anal photophores in the five Japanese specimens ranges as 

 follows: 6 + 6 (1), 6 4- 7 (2), 7 + 5 (3), 7 -f 6 (4), the two sides of each specimen 

 being listed separately. The sum of the two groups is either 12 or 13, while in 

 Hawaiian material it ranges from 13 to 15, with 14 prevailing (Gilbert, Bull. 

 U. S. Fish Com. for 1903 [1905], Part 2, p. 559). This smaller number in the 

 slender form may account for the smaller average number reported in South 

 Sea material as compared with that from Hawaii (Gilbert, Mem. Mus. Comp, 

 Zool., XXVI, 1908, p. 220). In the five slender specimens from the South 

 Pacific above referred to, the anal photophores are 7 + 6 on both sides of each; 

 in the four deep specimens from the same locality, the following numbers occur: 

 6 -f 7 (2), 6 + 8 (1), 7 + 5 (2), 7 + 6 (2), 7 + 7 (1). 



4. Dasyscopelus asper (Richardson). 

 Myctophum asperum Richardson, Voy. Erebus and Terror, 1845, p. 41, PL 



XXVII, figs. 13 to 15; habitat unknown. 



In addition to the characters which have been mentioned as distinguishing 

 this species from the nearly related D. spinosus, may be given the slenderer 

 form, the decidedly wider, blunter head, the fewer gill-rakers, and the absence 

 of the clusters of long spines, which in D. spinosus are attached to the scales 

 covering the ventral series of photophores. Comparing a Japanese specimen of 

 D. asper, 78 mm. long to base of caudal, with one of D. spinosus, 92 mm. long 

 to base of caudal, we have the following measurements in hundredths of length 

 as above indicated: 



