266 S. STILLMAN BERRY. 



when captured is curiously in accord with the behaviour of 

 Watasenia at the height of its own (spring) migration, at which 

 time Sasaki states that "they attacked us violently, biting our 

 hands with their jaws." Such as the Japanese catch in late 

 summer or autumn, on the other hand, are quiet and show little 

 vitality. 



From the relative emphasis laid upon the sources of the animal's 

 illumination by both Madeiran observers, but especially by 

 Nunes, it would seem that the ocular photophores of this Abralia 

 irradiate a conspicuously brighter light than the more abundant 

 organs of the body surface. This is very much what one would 

 superficially expect from the general appearance of these organs 

 in the dead animal. Turning again to the Japanese species we 

 find that Ishikawa ('13, p. 168) likewise states that of the three 

 types of photophores found in Watasenia scintillans, at least two 

 of which are entirely homologous with those of Abralia veranyi, 

 the organs of the outer integument come last in the intensity of 

 their light. Yet it must be remembered further that Sasaki, 

 working more extendedly on the same species, was unable to 

 make out any difference between the light of the ocular and that 

 of the integumentary photophores. However this may be, the 

 function of light production in both species would seem to be 

 essentially the same. The brilliance of the display stressed by 

 both Madeiran and Japanese observers, coinciding as it does in 

 each case with the schooling habit, the nocturnal migration, and 

 the period of sexual activity, is most readily interpreted as a 

 mating phenomenon, at least in very large part. I do not mean 

 by this that the sexes actually recognize one another's different 

 nature by means of corresponding differences in the luminosity 

 of male and female, although at the same time the possibility of 

 such recognition should not be too quickly excluded from con- 

 sideration merely because Sasaki, who inquired into this aspect 

 of the question quite particularly, found himself entirely unable 

 to distinguish the sexes merely by the light of the animals at night. 

 For there is another important way in which the photogenic 

 function could serve an animal behaving as Abralia veranyi does 

 during the reproductive season, and that is by simply furnishing a 

 visual method by which the schools can assemble or keep together 



