MOSER ET AL.: MYCTOPHIDAE 



221 



• Incorrectly 15-27 in Paxlon, 1972 



(1977) and Hulley (1981) on Atlantic species and McGinnis 

 (1982) on Southern Ocean species. 



Most lantemfishes make extensive vertical migrations from 

 mesopelagic depths to the upper waters at night, some reaching 

 the surface (Paxton, 1 967). The fisheries potential of myctophids 

 and other mesopelagic fishes has recently been reviewed (Gjo- 

 saeter and Kawaguchi, 1980). Adults range in size from 20-300 

 mm (Kreflt, 1974) and have a life span of from one year in 

 some tropical species (Clarke, 1973) to more than five years in 

 the few temperate species that have been studied (Smoker and 

 Pearcy, 1970; Gjosaeter, 1973: Kawaguchi and Mauchhne, 1982). 



Eggs 



Myctophids are oviparous and presumably all produce plank- 

 tonic eggs although such have been reported for only two species. 

 Sanzo (1939a) indicated that mature ovarian eggs of E. rissoi 

 have the following characteristics: round shape; 0.80-0.84 mm 

 diameter; segmented yolk; single oil globule, ca. 0.28 mm di- 

 ameter; smooth chorion. He illustrated a planktonic egg with 

 similar characteristics and tentatively identified it as that o( E. 

 rissoi. Robertson (1977) described the planktonic egg of Lam- 

 panyctodes hectoris as follows: weakly oval; long axis 0.74-0.83 



mm, short axis 0.65-0.72 mm; strongly segmented yolk; single 

 oil droplet, 0.21-0.23 mm diameter: narrow perivitelline space; 

 chorion smooth and delicate. He based his identification on the 

 similarity of these eggs and mature ovarian eggs of running ripe 

 L. hectoris captured at the same time by trawl. 



We have observed planktonic eggs similar to those described 

 by Robertson (1977) but have not found them with advanced 

 embryos that could be matched with co-occurring yolk-sac myc- 

 tophid larvae. The fact that these and other types of eggs ten- 

 tatively identified as myctophids occur in relatively low abun- 

 dance compared with myctophid larvae led Moserand Ahlstrom 

 (1970) to suggest that the fragile chorion breaks in contact with 

 plankton nets and the embryo is extruded through the mesh. 



Larvae 



Moser and Ahlstrom (1970) reviewed the literature on myc- 

 tophid larvae: however, numerous recent contributions have 

 advanced our knowledge of the group and are listed in Table 

 61. Of the 32 recognized genera of myctophids, larvae have 

 been described for all but Hintonia. The larval stages of myc- 

 tophids provide sets of characters that are useful at levels of 

 systematic analysis from species separation to hypotheses of 



