460 



DR. J. P. GEMMILL ON THE CILIATION OF THE 



slanting upwards and thus feeding the currents noted 

 under («) ; (c) in the spaces between the gonads ciliation 

 is absent except towards the centre of tlie bell where it 

 is feebly upwards {i.e., towards the manubrial junc- 

 tion) ; [d) below the floor of the stomach the ciliation 

 is strong and inwards towards the manubrium, the 

 surface of which is likewise strongly ciliated in the 

 direction of the mouth-opening. 

 3. Tentacles. — The tentacles show weak ciliation fiom their 

 attached to their free ends, except on their inner sides 

 near their bases where they are ciliated more strongly 

 and in the opposite direction. 



Text-figure 6. 



Diagram (vertical section) to illustrate ciliation of Melicertidiiim. The arrows 

 indicate the direction of the ciliary currents. See explanation in text. 



1, Mouth-openino-; 2, cavity of manubrium ; 3. stomach ; 4, radial canal ; 

 5, ring canal ; 6, tentacle. 



We may judge that the ciliation of the gastrovascular lining 

 subserves in the first place the mixing and transportation of 

 food, and that it is also capable of aiding the ingestion of 

 small food particles and the evacuation of the sexual products 

 through the mouth. The ciliation of the sub-umbrellar surface 

 will gather small food particles towards the niouth- opening. 



