Dr. Johnston on Scottish Mollusca. 119 



cream-coloured shadings, the brown disposed in some places 

 in darker patches. Middle of the back naked ; the smooth 

 space divides the branchial processes, which are very nume- 

 rous and arranged in close indistinct rows along the sides, 

 sloping backwards ; they are slightly compressed, lengthened, 

 unequal, those next the foot being the shortest. When ex- 

 amined narrowly > they are seen to be mottled by the configu- 

 ration of then' interior structure, and when compressed be- 

 tween plates of glass it will be found that there is always a 

 transparent circular spot at the apex. Head depressed ; the 

 mouth terminal, subinferior, encircled with a dilatable lip, and 

 furnished interiorly with a pair of rather large thin oval cor- 

 neous jaws, twisted into a tooth-like process at the apex, so 

 that they somewhat resemble the shell of a Sigaretus. Tongue 

 armed with numerous rows of transverse narrow corneous la- 

 minae finely pectinated on the free margin. Tentacula conical, 

 nearly equal, veiy contractile ; the inferior originating at the 

 sides of the mouth ; the superior placed on the back, and an- 

 nularly wrinkled. From the bases of the inferior a dark line 

 runs backwards to the superior tentacula, and forms a trian- 

 gular mark above the mouth, but this is often absent. In the 

 centre of the back there is a tumid spot, indicating the posi- 

 tion of the heart, the pulsations of which are often very per- 

 ceptible. Foot watery white, with a thin rather broad undu- 

 lating margin, prolonged at the anterior angles into an acute 

 process. 



This curious snail crawls slowly, feeling its way with the in- 

 ferior tentacula. The superior cannot be used for this pur- 

 pose, but they are in constant motion during the animal's 

 progress, and appear to be of essential service ; they are often 

 shortened, so as to appear like mere tubercles, but there are 

 no sheaths for their recession and protection. If the finger is 

 placed in the plate, about an inch before the creature, when 

 active and creeping, it will stop, turn back, and agitate the 

 tentacula, and then pass on to a side. The fasces are dis- 

 charged in pellets, like those of mice ; and when the animal 

 is dying, a small quantity of an orange fluid sometimes escapes 

 from one of the lateral apertures. It is not common in Ber- 

 wick Bay, but in spring a few specimens may generally be 



