THE CHARACTERS OF THE DEEP-SEA FAUNA 79 



by a simple continuation of the cuticle of the body 

 wall. The granular substance contained in the tubes 

 is most probably the seat of luminosity. 



B-_ 



Fig. 7. — Head of Pachystomias microdon (after Von 

 Lendenfeld). A, anterior sub-orbital phosphor- 

 escent organ ; B, posterior sub-orbital phosphor- 

 escent organ. 



As a type of the glandular organs we may take 

 one of the sub-orbital organs found on the head of 

 Pachystomias microdon. 



In this fish there are two very conspicuous white 

 organs immediately below the eye. The anterior 

 one, which lies below and in front of the eye, is oval, 

 with its upper margin slightly concave. In section 

 it is seen to be surrounded by a thin layer of black 

 pigment, and to consist of a reticular glandular 

 substance in which is embedded a hammer-shaped 

 lens-like body. Between these two structures there 



