they ai^G stored in the cavities or the organ and especial- 

 ly of that part first for-med {fif^s. G3,64, ov. ) wh.ich 

 serves as a duct for the rest of tho orf^an. The real 

 sexual d\act is remarkably short. It is formed as an ecto- 

 dermal invagination which is already present in specimens 

 2 mm. lonf^, but which does not break through till sexual 

 maturity. 



In the adult Teredo, the sexes arc separate. How- 

 ever, young specimens (1-4 cm, long) of X. fimbriata are 

 very frequently hermaphrodite. As in all such cases the 

 sperms are developed first, it appears as if the species 

 -^ may be prolfiandrous . In the adults, I have observed no 



external differences between tiie sexes. However, in the 

 male, there is a remarkable development of mucous gland 

 cells on the dorsal side of the epibranchial cavity; while 

 in the f eir.ale , they are not unusually developed in this 

 region. 



