OF NORTHUMBERLAND AND DURHAM. 29 



of the head and before the eyes, sufficiently distinguish it from 

 the other genera of the family. The animal is white and retrac- 

 tile within the shell, from which it is seldom much protruded, 

 keeping its eyes under the protection of the transparent shell, 

 through which it looks as through a window. This practice we 

 have noticed in several of the Mollusca, whose shells are trans- 

 parent. It has no gizzard nor operculum. 



Family. AcTiEONiD^, UOrhigny. 

 21. ACTION, Montfort. 

 1. A. TORNATILIS, Linn. 



Valuta tornatllis, Mont. Test. Brit. 231. 



From deepish water, rather rare. Occasionally found in the 

 stomachs of fish. 



The animal of this genus comes very near to that of Bulla, 

 having a broad lobed disc in front, without tentacles. We find, 

 too, that the branchial aperture is lateral, the cloak being 

 closed across the front, and open only on the right side, which 

 further confirms us in assigning it a place in this order. The 

 operculum can scarcely be considered of more than generic im- 

 portance. 



Order. PULMONATA, Cuvier. 

 Family. Limacid^, Fleming. 



22. ARION, Ferussac. 



1. A. ater, Linn. (Common black Slug). 

 Avion ater, Gray Turt. Man. 104. 



In woods, fields, and hedges, very common. 



Ferussac considers the black head and tentacles, and the trans- 

 verse black lines round the margin of the foot, to be the only 

 permanent distinctive characters in this very variable species. 

 The varieties we have observed in this neighbourhood are the 

 following : — 



1. Entirely black. 



2. Black, with the sides of the foot yellow or orange. 



