TROCHUS. TOP-SHELL. 189 



about half the surface of the base white, the latter appear- 

 ing as if worn flat : aperture roundish-oval, with a tooth- 

 like projection in the middle of the pillar, and sometimes 

 a small indenture like an incipient perforation behind it : 

 diameter an inch ; height an inch and a quarter. 

 On many rocky,coasts. v. v. 



7. Trochus Ziziphinus. Livid Top-shell. 



Lister, pi. 61G. f. I Pennant, pi. 83. f. 1 Da Costa, 

 pi. 3. f. 2 Donovan, pi. 52 -Dorset Cat. pi. 16. f. 3, 4. 



Shell conic, strong, finely pointed, with seven or eight 

 spires, which are separated by a raised smooth flattish cir- 

 cular belt, and obscurely striate or ridged in the same di- 

 rection, sometimes slightly beaded at the very tip which is 

 purple; the base obscurely striate circularly, and very 

 finely wrinkled across : color livid white or pale purplish 

 red, with red or dark purple longitudinal blotches, which 

 are very distinct on the belts and at the base, crossing them 

 in a regular banded manner ; inside white, perlaceous, 

 opake : aperture a little flattened and angular, with a slight 

 projection where the pillar begins to thicken : diameter 

 hardly an inch ; height something more. 



Variety A. Quite white, with the volutions more dU 

 stinctly defined. 



Variety B. With the volutions separated by a hollow 

 broad deep division, and wrought with indistinct spiral 

 ridges : from the lip to the pointed end also runs a deep 

 concave groove. 



Trochus discrepans. Brown, Wern, Soc. ii. pi. 24. f. 4. 



On most rocky coasts. The variety B. w r as found in Bel- 

 fast Lough, by Miss Templeton. v. v. 



8. Trochus Conulus. Cone Top-shell. 

 Pennant, pi. 33. f. 2 Donovan, pi. 8. f. 3. 



Shell thin, semitransparent, regularly conic and taper- 

 ing to a very fine point : spires ten, strongly striate circu- 

 larly, and separated only by a fine line, the five or six up- 

 per ones strongly beaded, and all of them more or less ob- 

 scurely so : color livid white or pale horn-color, faintly 

 marked with longitudinal purple blotches, which are only 



well 



