284 THE VOYAGE OF H.M.S. CHALLENGER. 



Exceptionally also simple ocellar organs are found attached to the outer surface of 

 the body and apj^ear as spherical projections. 



The lateral line may be converted into a series of ocellar phosphorescent organs, 

 every one of the scales which cover the lateral slime-canal bearing on its outer surface a 

 phosphorescent organ connected with the tissue below by a central perforation of the 

 scale. 



We have, therefore, the following six kinds of regular ocellar phosphorescent 

 organs : — 



1. Regular ocellar simple phosphorescent organs sunk in the body, without 



pigment coat and without reflector. 



2. Regular ocellar simple phosphorescent organs sunk in the body, with pigment 



coat and without reflector. 



3. Regular ocellar composite phosphorescent organs sunk in the Ijody, without 



reflector. 



4. Regular ocellar composite phosphorescent organs sunk in the body, with 



reflector. 



5. Regular ocellar simple phosphorescent organs attached outside to the body. 



6. Regular ocellar orsjans attached to the differentiated lateral line. 



The irregular glandular phosphorescent organs are always found on the head, and 

 besides, sometimes also on the sides of the body (Astronesthes), on the tail (some species 

 of Scopelus, Leydig), and on specially differentiated barbels {Ojwstwnias micripnus, 

 Malacosteus indicus). 



These have not been taken notice of hy Ussow ; they are designated by Leydig as 

 " Leuchtorgane." 



Six kinds of glandular organs are met with : — 



1. Glandular organs scattered irregularly. 



2. Glandular organs on the lower jaw. 



3. Glandular organs on the barbels. 



4. Glandular organs under the gill-cover. 



5. Suborbital, highly differentiated glandular phosphorescent organs without 



reflectors, and 



6. With reflectors. 



These may accordingly be with or without reflectors. A pigment coat is, how- 

 ever, invariably present in all the different kinds of irregular glandular phosphorescent 



