14 THÉEL, HERMAPHRODISM IN HOLOTHURIDS. 



As the genital cavity stånds in open communication with 

 the tubes, the stronia is pierced by combining canals, corres- 

 ponding in number to that of the tubes themselves. All the 

 canals are lined with ciliated epitheliura-cells like those which 

 invest the cavity itself and their walls are even and devoid 

 of folds. It is first towards the periphery, and just on the 

 transition where the canals pass över into the tubes, that a 

 series of longitudinal folds appear. Thus, in a section of the 

 peripheral part of the genital basis, the lumen of the canals 

 presents the aspect of a more or less irregular står. The 

 ciliated investment also ceases where the folds take their 

 origin. 



Longitudinal section through the naked posterior portion of the genital basis 

 where the "maculae" are to be seen. a hollow remains from obliterated foUicle 



tubes. Magnified. 



From sections through the hinder naked portion of the 

 genital basis, where the maculee and protuberances have their 

 place, we also discover that close inside them is situated a 

 correspondent hollow, with the confining walls in a state of 

 obliteration or atrophy. In those forms (comp. specimens 9 

 and 10) where the posterior end of the genital basis is very 

 significant by its size and colour, this work of destruction had 

 advanced so far that that part of the basis encloses only a 

 number of close-lying hollows bounded by thin walls devoid 

 of all epithelial lining, the surrounding tissues having been 

 totally destroyed, or being in state of dissolution. Probably 

 most of the hollows have also löst their communication with 

 the canals. 



