Sollas — On " Ccecal Processes " of Shells of Brachiopods. 319 



cases there appears to be more than one terminal cell. The inn* r 

 end of the terminal cell appears to be prolonged into a fibril, 

 which can sometimes be traced into continuity with the nucleus 

 on the one hand, and with the axial fibre on the other. The 

 outer end of the cell abuts against the lower face of the perios- 

 tracum, and thus ends smoothly and abruptly, not giving off hairs 

 or any other processes ; the fine striation which occurs at the end 

 of the cell, and which has been figured and described by Yan 

 Bemmelen, being of another nature. The periostracum imme- 



m = mantle. n = nerve cell. s = shell. t = end of ccecal process. 



diately over the end of the tubule appears to easily separate from 

 that surrounding it, since I find the end organs adherent by 

 means of the [overlying periostracum to the base of the incrusting 

 sponge, while the rest of the periostracum has disappeared from 

 around them, i. e., been torn away in the process of cutting. 



Tracing the ccecal tube inwards, the axial fibre is continued 

 into the nervous layer of the mantle, as already mentioned ; the 



