SEA-FISHEEIES LABORATORY. Ill 



made up rather of very fine fibrillae ruuuiiig in various 

 directions. The lateral excretory canals approach each 

 other and finally fuse near the extremity of the appendix. 

 Lonnberg describes a terminal vesicle, but this is repre- 

 sented in my sections bv the common part of the main 

 canal system and there is no real vesicle, only a cavity 

 having a stellate figure in sections. In close proximity 

 to the lateral canals, internal to tliem in the body but 

 external in the appendix, are two peculiar plexuses of 

 vessels. These are very narrow in calibre, have 

 relatively thick, homogeneous walls, and anastomose 

 with each other repeatedly. They appear to be excretory 

 capillaries. 



Nature of the Ort/d/i/sin . Cocnoiiioi- [ijius Im (/inifii/n 

 is certainly a larval form, and it may be that it corre- 

 sponds to some adult Tetrarhynchid already described 

 from some large animal, such as a porpoise or shark 

 (since the host is itself a fairly large fish). But it differs 

 in several respects from the typical plerocercoid larva 

 of known species of Tetrurhyuchvs. The " cephalic 

 segment " (bothridia and ])roboscidial ])arts) correspond, 

 but the "post-cephalic segment" differs greatly, thus 

 muscles and excretory canals are not present behind the 

 scolex, except in the walls of the receptaculum scolicis, 

 and then they form part only of the integumentary 

 system. The appendix, too, is something f|uite distinct. 

 What the organism suggests is the scolex and the 

 unsegmented " neck" region of a Tetrarhynchid such as 

 T. eriiiaceus. 



No trace of genital organs is present. Lonnberg, it is 

 true, describes the " anlagen " of ovaries, testes and vasa 

 deferentia in the appendix of his specimen, but he gives 

 no figures, and I cannot help feeling that he has mistaken 

 the knots of excretory ciipiUary vessels for these organs. 



