144 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



With regard to their purpose, no proposal can be 

 confidently advanced. That which occurs to the mind 

 first is, that they may assist in absorbing waste products 

 out of the coelomic fluid, forming them into a shape 

 suitable to excretion, and then casting them out. In 

 favour of this, we have the analogy of the ciliated-pots 

 of that curious animal Sipunculus nudus (fig. 6). These 

 are globes consisting of one transparent cell, which is 

 furnished with a sort of crown of cilia, set in a ring of 

 firm consistency. The ring appears to me to be nucleated, 

 that is to say, to be a second cell, though that is not the 

 received description. 



These ciliated-pots may be observed in a fresh specimen 

 of the hsemolymph, creating circles of disturbance amongst 

 the remainder of the corpuscles. When brought to rest 

 by the pressure of a cover glass, their shape can be made 

 out ; and it can also be ascertained — and this is the point 

 on which I wish to lay stress — that they have collected 

 within their ring of cilia, a mass of brownish debris, 

 evidently the waste products they have met in the coelom. 



That is so much direct evidence that these curious and 

 elaborate corpuscles have an excretory function. It is 

 possible that the rod and bow-cells collect excretory 

 matter, in an analogous, though not so obvious a way, 

 and with it build up the rods and bows. 



On the other hand, it may be argued that ordinary 

 phagocytes are present in all these worms to subserve 

 excretion, and that our special corpuscles must have other 

 special functions. 



The only other function which occurs to me as likely 

 is one in connection with the defence of the animal 

 against hostile organisms. In Trophonia I have found 

 structures in the coelomic fluid which were obviously of 

 this nature (fig. 7). These were solid figure-of-8-shaped 



