OÎT LUMINOUS ORGANS OF FISHES. 7 



Some lens-cells are found in stages intermediate between 

 those described above, showing a brick-red border around the 

 black central mass or granular contents inclosing a homogeneous 

 remnant in the iuterior. 



These changes of the lens-cells can be observed easily 

 in E. lucifer, while in frontimaculatus they are much obscured 

 by the general thinness of the epidermis and the weaker develop- 

 ment of the lens-cells. 



The linear photophores are more or less of a similar struc- 

 ture as the punctate ones, and are hardly distinguishable from 

 these in transverse sections. The most conspicuous point of 

 difference between the two lies in this, that in the linear pho- 

 tophore the lens-cells are more numerous and lie closer together 

 than in the punctate one, besides being arranged usually in two 

 layers scarcely leaving space enough for epidermal cells to lie 

 between. 



Luminescence, 



The luminescent phenomena were observed on a number 

 of E. frontimaculatus which were fortunately brought alive to 

 the Misaki Station. 



In ventral aspect, nearly the whole surface of the fish 

 could be seen as a faint, whitish, phosphorescent body, when a 

 proper stimulus was applied to it. At the bases of paired fins, 

 in the postanal region and in two discontinuous parts of the 

 caudal area, the luminosity was somewhat stronger, while the 

 eyes, the mouth, the mandibular spaces (a pair of narrow 

 triangular spaces on both sides in front of the gill-clefts, with 

 apices directed rostrad and mediad), the anal region and the 



