DESCRIPTION OF RECENT SHELLS. 99 



aperture semi-ovate ; pillar-lip broadly reflected on the columella, 

 behind which is an elongated umbilicus, extending" nearly to the 

 base of the shell ; outer lip thin and crenulated on the exterior mar- 

 gin by the ribs ; length upwards of half an inch ; diameter of body 

 nearly three-eighths. — Dredged from deep water in Rothsay Bay, by 

 James Smith, Esq. — B. 



It has been since found by Mr Jeffreys at Oban, and named by 

 him " Trichotropis acuminata."* 



3. TROCHUS PERFORATUS. N. S.- 

 Plate I. Fig. 3, 4. 



Trochus perforatus. — Brown's Illus. Conch. Britain and Ireland, 

 2d edition, p. 18. 



Shell subconic, strong, with five slightly-raised volutions, termi- 

 nating in an obtuse, perforated apex ; whole surface invested by a 

 thick, papillose, shagreen-like epidermis, of a brownish-drab colour, 

 beneath which the shell is covered with strong, smooth, spiral striae ; 

 colour of a greenish-ash, and ornamented by obliquely longitudinal, 

 fine, reddish-brown lines ; base of the body subcarinated, and a little 

 rounded beneath ; aperture subquadrangular, pearly within ; inner 

 lip thickened and slightly reflected over the umbilicus, which is 

 small and penetrating to the apex ; diameter at the base nearly six- 

 eighths of an inch ; height about five-eighths. 



Dredged in deep water in the Kyles of Bute, by James Smith, 

 Esq. of Jordanhill. 



This shell was at first mistaken by us for a variety of Trochus cine- 

 rarius, but on closer examination we found it to possess very diffe- 

 rent characters. It differs from all the other British Trochusidee in 

 its being invested by a very thick epidermis ; and its subcarinated 

 form at the base, with the colour and character of its markings, and 

 less intense by nacred reflections, distinguish it from Trochus umbili- 

 catus. It is considerably more depressed than T. littoralis." — B. 



4. TROCHUS MARTINI. N. S. — Smith. 

 Plate I. Fig. 26. 

 Shell conical, sides of the volutions flat, well defined by the suture, 

 and terminating in a fine pointed apex ; the whole shell covered 

 with five or six tuberculated spiral ridges, which can only be dis- 

 tinctly seen by the aid of a lens, the lower ridge of each volution 

 being more prominent than the others ; base imperforate, flat, and 

 somewhat concave, furnished with numerous tuberculate, concentric 



* An Trichotropi3 Borealis. Lowe. Zool. Journ. ? 



