182 MALACOZOA. GASTEROPODA. CYCLOBHANCHIATA. 



2. Patella Icevis. Smooth Limpet. 



Shell of moderate thickness, and horny appearance, with 

 the outline of the mouth oval, the apex obtuse, much nearer 

 the smaller end ; the surface concentrically striate, generally 

 with well-marked growth-lines, one of which is near the apex; 

 the colour generally yellowish-brown, frequently with some and 

 occasionally with numerous rays of purple or brown from the 

 apex ; the inside glossy, opaline ; the margin thick and plain. 

 Length about ten-twelfths of an inch. 



It varies in form, in the position of the apex, and in colour, 

 being sometimes dusky, or brown, or yellowish-grey, with or 

 without bands. 



Occurs on fuci, especially the stalks of the tangle ; not un- 

 common on the rocky coasts : Stonehaven, Aberdeen, Cru- 

 den, Peterhead, Fraserburgh, and Gamrie. 



Patella lsevis. Penn. Brit. Zool. iv. 144. PL 90. lowest figure. — 

 Patella caerulea. Mont. Test. Brit. Suppl. 152. — Patella laevis. 

 Flein. Brit. Anim. 287. — Patella pellucida. Lamk. Syst. vi. 334 ; 

 Ed. 2. vii. 540. 



3. Patella pellucida. Transparent Limpet. 



Shell very thin, fragile, transparent, with the outline of the 

 mouth oval, the apex incurved, obtuse, close to the smaller 

 end ; the surface with about twenty-eight very faint ribs and 

 intermediate striae, together with faint concentric striae, more 

 marked toward the margin, which is thin and even ; the 

 colour generally yellowish-brown or dusky, with some light- 

 blue interrupted rays from the apex ; the inside greyish-white, 

 toward the margin horny. Length about two-thirds of an 

 inch. 



It varies in being more or less convex, with the apex nearer 

 to the edge or more remote from it, in colour, and in the num- 

 ber of blue lines. In all stages it is easily distinguishable 

 from Patella lasvis, with which however many authors have 

 confounded it. 



Common on fuci near low-water mark, on all the coasts; 

 and frequent on the beaches. 



Patella pellucida. Linn. Syst. Nat. i. 1260. — Patella pellucida. 

 Penn. Brit. Zool. iv. 143. PI. 90. f. 150.— Patella pellucida. Mont. 

 Test. Brit. Suppl. 152. — Patella pellucida. Flem. Brit. Anim. 

 287.— Patella pellucida. Lamk. Syst. vi. 334; Ed. 2. vii. 240. 



