^0 THÉEL, HERMAPHRODISM IN HOLOTHURIDS. 



faculty of producing eggs and sperma during the wliole of that 

 period of time. Mesothuria intestinalis appears to form a remar- 

 kable exception from the rule, in-as-miich as the emptied bund- 

 les of tubes successively become destroyed and obliterated as 

 soon as the animal has spawned. From what I have learned 

 from the extensive literature on the Holothurids, a similar 

 case has not been noticed before. 



On the preceding pages I several times used the term 

 "bundle of genital tubes" by which I mean eaeh tuft of tubes 

 running out from a common, more or less elongated, cylin- 

 drical stem. With regard to the term "generation of genital 

 tubes" I mean, of course, all such bundles which contain the 

 same sexual products. 



A verv young follicle bundle, though somewhat older than those in the for- 

 mer wood-cut. HigMy magnified. 



As before mentioned, the bundle consists of a stem sup- 

 porting a tuft of dichotomously-branched tubes varying in 

 number in different bundles. In the male bundles the ripe 

 tubes are narrower, cylindrical, and are of a milk-white colour. 

 The female tubes, on the contrary, are elongated fusiform, 

 and of a reddish colour. In one and the same individual, the 

 male and female products very seldom reach maturity at the 

 same period of time. 



The number of bundles appears to change considerably. 

 As a rule, they seem to reach their maximum-development 

 during the summer-months and at the beginning of the autumn. 



