IN PORICHTHYS. 51 



eral plan. A lack of literature renders it impossible for me 

 to go into comparisons with previously described types as 

 I could wish. 



They but very remotely resemble those described by 

 Ussow 1 in Scopelus, while of all the types described by 

 Dr. von Lendenfeld, 2 they are more nearly related to his 

 "simple, regular ocellar phosphorescent organs with pig- 

 ment," as will be seen from the following abstract of his 

 description. He says this type consists of "a sac," "about 

 as deep as wide, cylindrical, rounded below, and opening 

 outwards by a circular aperture, which is covered by a con- 

 tinuation of the cuticle." This sac " is formed of a dense 

 layer of pigment," and the " lower proximal part of the sac 

 is occupied by radially placed pyramidal gland-tubes, close- 

 ly packed, and therefore flattened against each other. Their 

 wide distal ends are rounded and nerves and blood vessels 

 radiate upwards between the tubes." "These tubes are filled 

 with spherical or slightly irregular granular cells." "In the 

 centre of the organs within the terminations of the gland- 

 tubes, there is a space, which is filled with a granular se- 

 cretion. The portion of the organ underlying the cuticle 

 is also granular, but it is easy to perceive that this portion 

 of the glands is occupied by cells." 



This type of organ has no spicular reflecting layer what- 

 ever, while in Porichthys, the reflector, next to the lens, 

 is the most noticeable part of the organ. In fact the gen- 

 eral shape is the only thing they have in common. 



EXPLANATION OF PLATE IV. 

 a = anal row. 

 aa = angular row. 

 c = connective tissue capsule. 



J M. Ussow, Ueber den Ban der sogenannten Flecken eiuiger Knoeheniische, Bull. 

 Soc. imp. des. Nat. Moscou, t. LIV, So. 1. p. 79, 1879. 



a B. von Lendenfeld, Report on the Structure of the Phosphorescent Organs of 

 Fishes, Challenger Reports, Zoology, Vol. xxn, pp. 277-329, plates LXIX-LXXII. 



