14 A STRANGE TENANT. 



under the shell of the fissurella ; and, thanking 

 his lucky stars for such a fortunate deliverance, 

 wished to make the best of his liberty, and rejoin 

 his friends. But in displacing other shells, I 

 found in nearly every one a similar tenant: the 

 secret was discovered the worm was a parasite, 

 that lived in peace and good-fellowship with the 

 Keyhole, recalling to my remembrance Oppian's 

 lines on the pinna and the parasitic crab 



One room contains them, and the partners dwell 

 Beneath the convex of one sloping shell, 

 Deep in the watery wastes the comrades rove, 

 And mutual interest binds their mutual love. 



That the parasite worm does no harm is clearly 

 proved by the healthy state of the mollusc in 

 whose shell it takes up its abode. How far 

 mutual interest may conduce to mutual friend- 

 ship, I am unable to say. 



On more carefully examining the position of 

 the worm, I found it was invariably coiled away 

 in a semicircle under the foot, like a ribbon on 

 its edge, never flat. This seems to me a wise 

 provision; for the pressure of the muscles when 

 the limpet grips the rock would crush a soft- 

 bodied worm to death, if flat ; but by being edge 

 on, which is the position chosen, all risk of harm 

 is avoided, as it fits in a cleft between two layers 

 of soft material. 



