of p. (H.) crockeri, again with no overlap in values. However, due to the paucity of specimens, 

 it cannot now be said that the limits of variability of P. (H.) beckeri have been approximated. 



Protomyctophum (Hierops) thompsoni 



(Chapman, 1944) 



Fig. 12— Protomyctophum (H.) thompsoni. male, 47.5 mm. (Photophores retouched). 



Description 



D. 12 (11-13); A. 23 (21-25); P. 15 (14-17); AO 16 (15-17); gill rakers 4 (3) -I- 1 -H 13 (12-15), 

 total 18 (16-20); vertebrae 38 (37-39). 



SAO in a distinct but very wide angle; SAOg slightly elevated above a line through SAO, -2. 

 SAOj usually before a vertical from VO.i, rarely at or behind this vertical. SAOj always nearer 

 SA0:j than to SAO,, usually twice nearer. Interorbital width usually half or less the width of 

 expanded distal portion of upper jaw. 



Precaudal luminous glands very similar to those of P. (H.) crockeri; supracaudal glands of 

 males average somewhat smaller (Fig. 3). Becker (1963b) stated that these glands begin to 

 develop in specimens of about 25 mm, but are sometimes lacking at 33-36 mm. 



Size: To about 52 mm. 



Least depth of capture: to 500 m at night. 



Distribution: This species occurs across the North Pacific Ocean, usually north of 40° N 

 (Fig. 9). It also occurs in the Bering Sea near the central Aleutian Islands, but is probably 

 carried there by currents through the many interisland passes. It has not been taken 

 elsewhere in the Bering Sea. No population structure is evident. 



Protomyetophum (Hierops) subparallelum 



(Taning, 1932) 



Fig. 13 — Protomyctophum I H.I suhparallchnn . female, 29.0 mm. From Andriashev 



(1962, p. 2.35, fig. 14). 



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