304 



A. TERAO ! 



continuous with, the above three layers of the general cuticula. They 

 are : the covering layer (/j), the outer lens body (/ s ) and the inner lens 

 body (/,). 



The covering layer of the lens differs in no way from the externalniost 

 layer of the general cuticula, like which layer it is uniformly very thin in all 

 its parts. In sectioning, the layer is easily torn away, especially if the 

 object is imbedded in paraffin. Both lieidcnhain's iron-haematoxylin and 

 borax-carmine stain the layer very deeply, much more so than they do the 

 remaining inner parts of the lens. Freeborn's picro-nigrosin stains it 

 faintly yellow, the Congo red yellowish-orange. The corresponding layer 

 of the general cuticula, outside the lens area, is affected by the stains in 

 exactly the same way, so that it may be said that the general cuticula, so 

 far as concerns its outermost layer, shows no differentiation whatever in the 

 parts overlying the photophores. Kemp ("io b), in his semi-diagrammatic 

 figure (Pl. LIV, fig. 3) of the photophores of .S". cliallengeri, has given a 

 special covering membrane to the lens but seems to have entertained some 

 doubt as to its real presence, for, in the text he has referred to it as a 

 structure which " possibly " exists. I almost do not doubt that the same 

 covering layer as that I have described above does exist in 6". cliallengeri 

 also ; since, the black bordering line, visible in the microphotograph given 

 by Kemp (Pl. LIII) and running continuously over the lens as well as over 

 other parts of the body surface, can well be interpreted as representing the 

 layer in question. 



The outer lens boby (/ 2 ) is a distinct and simple concavo-convex 

 thickening of the middle layer of the general cuticula, standing with its 

 outer convex and inner concave surfaces in direct apposition respectively to 

 the external covering layer and the inner lens body. Peripherally the outer 

 lens body becomes gradually thinner, passing over imperceptively into its 

 mother layer in the general cuticula. In unison with that mother layer, 

 the outer lens body stains uniformly red with Congo red, but somewhat 

 more faintly than does the inner layer of the general cuticula or the directly 

 adjoining stratum of the inner lens body. It takes up Heidenhain's iron- 



