452 



u. c. 



Fig. 5. — Transverse section of a gill-filament of Crepidula from the visceral region. 



( X about 67.) 

 D.C. Dorsal cilia ; I.e. Lateral cilia, which lash in the direction indicated by the arrow ; 

 v.c. Ventral cilia ; c. Gill-filament supports. 



APP/fOX/MATE D/PECT/ON OF 



our-Go/uc CL/ppEur 



D/PECVON W tVP/CPTME 

 LATEPAL C/UA LASH 



I LATEPAL C/L/A 



APPPOX/AfATE £>//?£ CT/ON Of MOT/O/V OE 

 FE££-SiV//7j--f//i'u E/LAMENT 



Fig. 6. — Posterior view of a gill-filament of Crepidula. (Drawn from a living filament 



of Crepidula. x 50.) 



idea of the forward movement would be conveyed if one imagined 

 a sheet of mucus bearing the food-particles being both drawn and 

 passed onwards into the food-pouch. 



The question now arising as to why the larger food-particles should 

 be caught in mucus and carried forwards, while the finer particles 

 travel onwards to the gill, is easily answered, but it is necessary first 



