o2 LAND AND FRESH-WATER MOLLUSKS. 
Anodons furnish a very favourite repast for 
the herons, and crows feed upon them. Pennant 
says, “that when the shell is too hard for their 
bills, they will fly with it to a great height, drop 
the shell on a rock, and pick out the meat when 
the shell is fractured by the fall.” 
This species is invested with a mite (Atag 
ypsilophora), which is so tenacious of life that 
they survive an immersion in boiling water. 
Famity CyYcCLADID®. 
The remaining British fluviatile bivalves be- 
long to the family Cycladide, characterized by 
the mantle-lobes being united at the posterior 
side to form one or two prominent contractile 
respiratory siphons. The foot is large and 
tongue-like. The shells are small, thin, and sub- 
‘orbicular ; the hinge-line with minute cardinal 
Fig. 3.—Pisidium umnicum, with its foot and siphon protruded. 
and lateral teeth, two cardinals, and a lateral on 
each side, in the left valve; in the right, one 
cardinal, and two laterals on each side. 
