132 MALACOZOA. GASTEROPODA. PECTINIBRANCHIATA. 



Fergus ; and Miss Macgillivray at Gamrie, in Banffshire. I 

 have found at Aberdeen, a most beautiful white individual, 

 with the apex purplish. 



Trochus zizyphinus. Penn. Brit. Zool. iv. PI. 80. f. 103. Tro- 

 chus zizyphinus. Mont. Test. Brit. 274. Trochus zizyphinus. 

 Lamk. Syst. vii. 23. Trochus zizyphinus. Flem. Brit. Anim. 323. 



2. Trochus conuloides. Conuloid Pyramid-Shell. 



Shell conical, with the pillar closed, the base flattened, the 

 aperture somewhat square, oblique ; the interior pearly and 

 iridescent ; the lip thin ; the last turns obtusely angulate ; all 

 the turns, eight or ten in number, flat, little-glossed, rude, 

 marked longitudinally with from three to five prominent nar- 

 row ridges, and corresponding broader grooves, the upper and 

 lower ridges larger, but the latter not forming a conspicuous 

 rim, as in the last species ; the colour reddish-white, with patches 

 of rose-red across the turns ; the base concentrically grooved 

 and radiatingly striulate. Height an inch and ten-twelfths, 

 breadth about the same. 



This species, generally confounded with the last, differs in 

 being much thicker, coarser, strongly ridged, with the spire 

 less pointed, its outline rather convex. It is abundant in the 

 Islands of Lewis and Harris. 



One specimen found by Miss Isabella Macgillivray, at 

 Gamrie, in BaniFshire, in September, 1842; others by Mr. 

 Murray, at Fraserburgh. 



Trochus conuloides. Lamk. Syst. vii. 24. 



3. Trochus Martini. Martin's Pyramid-Shell. 



Shell conical, with the pillar closed, the base flattened, the 

 aperture somewhat square, oblique; the interior pearly and 

 iridescent ; the lip very thin ; the last whorl angulate ; all the 

 whorls, eight or ten in number, flat, with from four to eight 

 cord-like ridges, beautifully granulato-crenulate with trans- 

 verse furrows, and on the lower margin and the angle of the 

 last whorl, a very prominent larger rope-like granulated ridge, 

 the granulations formed by the oblique striae or lines of growth ; 

 the lower surface grooved and crenulate, but less distinctly ; 

 the colour pale yellow, with some deeper blotches. Diameter 

 six-twelfths of an inch, height seven-twelfths. 



Two specimens, dead and partially decayed, brought up 

 by fishing-lines from deep water and hard ground, about 

 eight miles off Aberdeen, in March, 1842, both found by myself. 



