18 



THÉEL, HERMAPHRODTSM IN HOLOTHURIDS. 



nal cells which often reduce the central lumen to a minimum 

 (Pl. Il, fig. 14). In the same sections I found three to five, 

 sometimes more, cut ends of canals (Pl. I, fig. 6, 7) imbed- 

 ded in the connective tissue of the left wall of the duct, 

 and in other sections I have observed that some, at least, 

 of these cavities, apparently separate the one from the 

 other, intercommunicate and are twisted in such a manner 

 that a section has passed through the same canal twice, or 

 even several times. Besides, some views make it probable 



Transverse section of the genital duct. m, dorsal mesentery ; mm, mesenteric 

 membranes confining the genital sinns of Semper; sp, amassment of sperma- 

 tozoa; c, canals constituting the germinal cord in the left wall of the duct. 



Highly magnified. 



that the canals (or canal) protrude small branches. Never- 

 theless, from want of suificient material I am obliged to leave 

 undecided whether the germinal cord is built up of a single 

 highly wrinkled and plaited canal giving off small branches, 

 or if it is composed of a series of shorter wrinkled and branched 

 closed tubes. 



