Table 4.— Species of myctophids and number taken per tow for stations given in Table 2. 



50 m 100 m 200 m 300 m 450 m 500 m 



Species Stn. 48 49 58 68 57 69 61 67 52 76 60 78 



Electrona rissoi — — — — — — — 1 — — — — 



Hygophum proximum 1 2534 631 — 1216 



Diogenichthys atlanticus 3 3 4 — — 1 1 — — 1 — 5 



Myctophum aurolaternatum — — — — — 1 — — — — — — 



Myctophum asperum 3 — — 1 — — — — — — — — 



Myctophum nitidulum — 2 1 1 1 — — — 1 — — — 



Myctophum obtusirostrum 1 — — 1 — — 2 — — — 1 — 



Myctophum selenoides — — 3 — — — 1 — — — — — 



Myctophum spinosum — 2 2 — 1 1 1 — — — — — 



Symbolophorus evermanni 5 8983 — 12 — 1 — 1 



Diaphus drachmani — — — — — — 1 — — 1 — — 



Diaphus elucens 7 17 1 — 1 — — 3 1 1 — — 



Diaphus Iragilis 5 6 122 — 22 — — — — 



Diaphus jenseni — — 56 5 2 4 2 1 — — — — 



Diaphus longleyi — — 31 6 4 10 1 1 4 — 3 2 



Diaphus lucidus — — 4 4 — — — — — — — — 



Diaphus luetl<eni 2 — 4 — 3 4 1 — 2221 



Diaphus malayanus 67 10 1 2 1 1 — 2 — — — — 



Diaphus problematicus — — 2 — — — — — — — — — 



Diaphus regani — — 1 — — — — — — — — — 



Diaphus splendidus 7 — 46 14 6 2 5 3 — 2 5 1 



Diaphus termophilus — — — 1 — 73361 — 1 



Diaphus sp. (near mollis) 25 — 5 — 2 3 1 1 — 52 — 



Notolychnus valdiviae — — 25 3 4 25 3 1 1 — 8 — 



Lampadena luminosa — — 7 — — 2 — 1 — — 1 — 



Triphoturus nigrescens 8 314 — 5 27 8 2 31211 7 



Lampanyctus hubbsi 78 66 744 8 — 214 — 2 



Lampanyctus"niger" — — 43 23 34 127 13 31 42 11 1 28 



Lampanyctus nobilis — — — — — — 1 — — 1 — — 



Lampanyctus omostigma — — — — — — — — — 1 — — 



Lampanyctus steinbecki 1 — 1 3 1 4 — — — — — — 



Bolinichthys sp.' — — 1 — — — 1 2 1 — — — 



Bolinichthys long i pes 12 10 1 2 2 1 1 — 3 1 — 1 



Bolinichthys photothorax — — 2 — — — 2 2 1 — — — 



Ceratoscopelus warming! 90 123 25 2 10 12 11 14 1 8 5 3 



^Bolinichthys sp. is similar to S. supralateralis, but is apparently distinct and undescribed (R. K. Johnson, 

 Field Museum of Natural History, Chicago, III., pers. commun.). 



Several of these species are truly warmwater 

 cosmopolites (McGowan 1971). Hygophum 

 proximum, M. aurolaternatum, M. nitidulum, and 

 B. longipes occur in equatorial waters not only in 

 the study area, but widely throughout the east- 

 ern equatorial Pacific. Others, C. warmingi, 

 Diogenichthys atlanticus, and Diaphus fragilis, 

 apparently occur in equatorial waters only west of 

 ca. long. 130°W. 



Most of the 10 above species showed similar 

 trends in abundance with latitude; peak abundance 

 was at either lat. 3°30'N or at the equator. The 

 same trend is evident in the total numbers of 

 myctophids taken in deep tows (Table 3). (The to- 

 tal catches of the shallow tows tended to decrease 

 southward. This trend is not marked, and the ab- 

 sence of data from the equator is perhaps critical.) 

 A trend similar to that of the deep catches and of 

 the wide-ranging species has been noted in 

 zooplankton standing crop (King and Hida 1957). 

 The increases in abundance are probably related 

 to the higher primary productivity resulting from 

 the upwelling and subsequent northward trans- 



port of enriched waters near the equator (Crom- 

 well 1953; Murphy and Shomura 1972). 



Three species of myctophids which are abundant 

 at night in the upper layers near Hawaii and also 

 taken at the gyre center were conspicuously ab- 

 sent from the present samples. Benthosema 

 suborbitale, Diaphus schmidti, and a Diaphus sp. 

 similar to D. mollis (called Diaphus sp. A by Clarke 

 1973) are apparently restricted to the central 

 water mass-at least to the east of long. 145°W. 



Seven species occurred only or principally at the 

 northern two stations. Diogenichthys laternatus, 

 Gonichthys teniculus, Diaphus garmani, Lam- 

 panyctus omostigma, L. nobilis, and Notoscopelus 

 resplendens were taken only at lat. 12°N and 

 7°30'N. Diaphus problematicus was taken only at 

 lat. 7°30'N. Three of these species, D. problemat- 

 icus, L. omostigma, and L. nobilis, were captured 

 in the IK series at lat. 3°30'N, but in low numbers 

 (Table 4). It is clear that none of these species 

 occurred at lat. 3°30'N in abundance. 



Of these seven species, one appears to be widely 

 distributed in the central water masses and four 



637 



