3o8 jeffery: the mollusca of western Sussex. 



and consequently of food is situated in the genus 

 Fisidium, it having no influx siphon, a fringe of vibratile 

 cilia, whose function would appear to be to create a current 

 for the passing away of objectionable matter while the 

 folds of the mantle are temporarily closed, and probably 

 being very sensitive, to detect such matter in its passage 

 between the valves. I have most positively noticed a 

 side current caused by these cilia or other motive 

 power whatever it may be when the valves have been 

 either wholly or partially closed. The influx siphon of 

 the genus Anodonta and others as is well known is 

 clothed with a very perceptible fringe, or according to 

 Gray is bearded. 



I have also remarked that the edges of the valves in 

 P. fontinale are sometimes thickly fringed with a species 

 of Epistylus (Protozoa), which proba,bly find some 

 advantage in the way of obtaining food by the current 

 caused by the bivalve. 



P. pusillum. In similar situations to the last named, but less 

 frequently met with. 



P. nitidum. I have found this species in the deep ditches and 

 pits at Chidham. Not so generally met with as the 

 other species in this genus. 



Unio pictorum. Plentiful at Burton near Petworth in a 



tributary of the western Rother, and probably occurs 



in other branches of this river, which flows into 



the Arun. 

 Anodonta cygnea. Occurs commonly with the last named 



species and throughout the Arun waters. Also in the 



Chichester Canal. 



A. anatina. Burton and Wisboro Green. Have taken the 



variety complanata at Burton, 



J. C, Hi., April, 1882 



