considered Zoologically and Geologically. 221 



The Chitons are never taken dead, probably falling to pieces 

 after the animal's death. The Lucinae are always dead. 

 Rare, but taken oftener than once, are 



Trochus tenuis. Chiton fuscatus. 



Fusus linearis. Lima inflata. 



Natica Montagui. tenera. 



Rissoa reticulata. Modiola marmorata. 



Dentalium entalis. Astarte scotica. 



Chiton fascicularis. danmoniensis. 



Modiola discors. 



All these species are taken alive. The Lima inflata is al- 

 ways found in a veiy singular situation, imbedded in a mass 

 of coralline fibres, broken shells and fragments of millepora. 

 On breaking open the mass we find the Lima alive in the 

 centre, in a neatly constructed nest, the sides regularly 

 smoothed, somewhat resembling the bed of the Modiola im- 

 pact a of the South seas. I am not aware that this very re- 

 markable habit has ever been noticed. Neither Lima fragilis 

 nor Lima tenera are found in similar nests. The two species 

 of Astarte are found of nearly equal size, the characters of the 

 margin distinct in each. I regard the thickening of the mar- 

 gin in many species of this genus as specific in the full-grown 

 shell. 



The following species have occurred only once. In the 

 case of the three first, two specimens were taken of each, of 

 the others one only. 



Eulima Donovani. Pecten lsevis. 



Pleurotoma purpurea. Criopus anomalus. 



Area tetragona. Psammobia strigillata. 



The two Arcce were taken together, imbedded in the mud 

 filling the cavity of a large dead Modiola. They were alive. 

 The Pecten was attached to the stalk of a coralline. The 

 Psammobia was a dead valve. 



Naked mollusca are not uncommon on the bank, as might 

 be expected, seeing that it is very fertile in specimens of An- 

 tennularia antenni7ia,the favourite habitat of the smaller deep- 

 water Nudibranchia. The most common is Melibcea fragilis. 

 Formerly Tritonia Hombergi abounded of a very large size, 



