IN PORICHTHYS. 51 



eral plan. A lack of literature renders it impossi])le for me 

 togo into comparisons with previously described types as 

 I could wish. 



They but very remotely resemble those described by 

 Ussowi in Scopelus, while of all the types described by 

 Dr. von Lendenfekl,^ they are more nearly related to bis 

 "simple, regulär ocellar phosphorescent organs with pig- 

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

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

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

 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 " lowei« proximal part of the sac 

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

 ly packed, and therefore flattened jigainst each other. Their 

 Wide distal ends are rounded and nerves and blood vessels 

 radiate upwards between the tubes." "These tubes areßUed 

 with spherical or slightly irregulär granulär cells." "In the 

 centre of the organs within the terminations of the gland- 

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

 cretion. The portion of the organ iinderlying the cuticle 

 is also granulär, 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 fiict the gen- 

 eral shape is the only thing they have in common. 



EXPLANATION OF PlATK IV. 



a = anal row. 

 aa = angular row. 

 c = connective tissue capsule. 



^M, Ussow, Ueber den Bau der sogenannten Flecken einiger Knochenli8clie, BiiII. 

 Soc. inip. des. Nat. Moscou, t. Liv, No. 1. \). 79, 1879. 



2R. von Lendenfeld, Report on tlie Structure of tlie Phosphorescent Organs of 

 Fishes, Challenger Reports, Zoology, Vol. xxii, pp. 277-329, plates lxix-lxxii. 



