Fig. 43 — Capture localities for Diogenichthys atlanticus in the eastern Pacific Ocean. 



proportions, and photophore patterns. Mature males within a species group may be separated 

 on the basis of appearance and structure of the supracaudal luminous glands, but the in- 

 fracaudal glands of females are very similar throughout the genus. Immature specimens are 

 almost impossible to determine specifically, especially where geographic ranges overlap. 



The genus is worldwide in distribution. Although most species are essentially tropical, one 

 (possibly two) is found to about 45° N in the northwestern Pacific, and one to at least 55° S in 

 the southeastern Pacific (probably a new species). 



In the entire eastern Pacific Ocean only three species have previously been recorded, S. 

 californiensis, S. evermanni, and S. boops, but there may be five or six undescribed forms. 



The following key will serve to segregate at least the species groups to be found in the 

 eastern Pacific. 



Key to species groups of Symbolophorus 

 in eastern Pacific 



49 



