1 68 S. STILLMAN BERRY. 



are so weak that in carrying them from the sea to the aquarium 

 they wasted and died. As they wasted, the luminosity in ques- 

 tion became very feeble, and naturally with their expiration, 

 the light of the luminous organs gradually vanished altogether. 

 This being so, I then tried to observe the animals directly while 

 they were swimming in the net. But no good means were found 

 easily to distinguish the sexes on such dark nights, even with the 

 feeble light of the moon or of a lantern. 



"However in my examinations at night, no special variety of 

 the light could be found, the colour of the light being always the 

 same. And in one case, putting in a vessel and observing about 

 thirty specimens in a fishing boat while they were yet actively on 

 motion, I verified the fact that their luminosity is uniform. In 

 the morning, to my surprise, a male was found dead among those 

 30 specimens; this proves that it had the same colour of light 

 with the female on that night. The above data seem to prove 

 the fact that the colour of the light of the luminous organs is the 

 same in both sexes. 



"Again, in late July of the same year, I made another obser- 

 vation on the phosphorescence under consideration and then it 

 was quite evident to me that the luminosity of the brachial organ 

 was at this season noticeably feebler than in the spring. 



'The phosphorescence of the immature animal can never be 

 studied in Namerikawa, young ones thus far not being found 

 there." 



In the same paper (pp. 98-99), Sasaki incidentally records the 

 fact that he observed the photogenic property in living specimens 

 of the myopsid, Inioteuthis japonica Verrill ( = inioteuthis 

 (Naef)). These he found to be "discharging a faint cobaltish 

 light from a great luminous organ which is situated in the mantle 

 cavity near the ink-bag." From anatomical observations we 

 know that the luminous organs of this genus are essentially 

 similar to those of the nearly related if not actually congeneric 

 Sepiola. 



Lastly, Dahlgren (:i6, pp. 70-71) describes in a little greater 

 detail than before the photogenic behavior of Heteroteuthis 

 dispar, the myopsid species already observed by Meyer. He 

 writes: "When brought into the laboratory in good condition 



