126 



THE VOYAGE OF H.M.S. CHALLENGER. 



In all they are in the form of hermaphrodite masses projecting from the inner 

 surface of the wall of the peribranchial cavity, and developed on both sides. They are 

 near the posterior end and rather nearer the ventral than the dorsal edge, those on the 

 left side being in close relation to the rectum. 



In Culeolus murrayi there are several quadrate genital masses on each side, more 

 on the right side than on the left. Each mass consists of a spherical spermarium 

 surrounded by masses of ova. The different spermaria are connected by a delicate vas 

 deferens, so that all on the one side of the branchial sac have a common opening. 



In Culeolus perlucidus there is a single genital mass on each side, lying parallel with 

 the stomach, and having the excretory ducts directed posteriorly. In Culeolus recumbens 

 there are three genital masses on each side of the body, and each opens by a distinct ovi- 

 duct and vas deferens. In this species the rectum is distant from the stomach, and the 

 genital glands on the left side lie in the wide intestinal loop, while in Cideolus perlucidus 

 the rectum is in close contact with the stomach, the intestinal loop is narrow, and conse- 

 quently the genital mass lies outside on the dorsal edge of the rectum. 



The species of Culeolus may be distinguished by characters taken from the condition 

 of the branchial sac and tentacles alone, as shown in the following table : — 



Culeolus. 



Transverse vessels all of 



Transverse vessels of different 

 sizes. 



2 internal longitudinal bars 4 internal longitudinal bars Transverse vessels of 

 upon a fold. upon a fold. two sizes. 



Culeolus perlucidus. 



Culeolus murrayi. 



Transverse vessels of 

 three sizes. 



Culeolus wyville-tlioms 



Tentacles small, slightly branched, 

 all of much the same size. 



Culeolus moseleyi. 



Tentacles large, much branched, of two 

 sizes, placed alternately. 



24 tentacles. 



I 

 Culeolus recumbens. 



16 tentacles. 



I 

 Culeolus perlatus. 



