GASTEROPODOUS MOLLUSCA OF BERWICKSHIRE 39 



dually to the posterior extremity ; it is smooth, whitish, and closely in- 

 vested with a thin pellucid membrane, beneath which two strong satiny 

 ligamentous muscles are seen lying along the ventral surface, adhering 

 closely, and each of them divided into a broad and a narrow slip. 

 These arise near the base of the foot, and they extend to within a line 

 or so of the anus, forming there a circular band with a laciniated mar- 

 gin ; and the office of the ligaments is, doubtless, to draw the snail 

 within the shell, or push it outwards, according as the one or the other 

 end is made the fixed point. The collar is very thick and fleshy, and makes 

 a complete circle, through which the foot can be pushed at pleasure. 

 The foot forms the anterior portion of the body ; it is cylindrical, 

 thick, fleshy, pointed with a conical process and cleft below ; and in 

 the groove we see the mouth in the shape of a compressed process, pro- 

 jecting forwards, and with its edge fringed with short tentacular pa- 

 pilloe. At the root of this process the branchisc originate, forming two 

 bundles of numerous clavate filaments. The mouth is furnished with 

 a ribbon-like tongue, armed with cartilaginous or homy blunt den- 

 ticles, set in two rows. Anus posterior and terminal, opening by a 

 wide slit directed to the dorsal aspect. 



2>, striatum^ Brown, Illust. pi, 1, fig. 8. " Found by me at Holy 

 Island, coast of Northumberland," Capt. Brown. 



A Supplement to Dr Johnston's Catalogue of the Berwickshire 

 Mollusca. By Robert Maclaurin, Coldingham. 



Pleurotoma. Lamarck, 



** Shell fusiform, turrited, aperture oval, with a more or less elon- 

 gated canal at the base ; outer lip with a notch near the suture ; oper- 

 culum horny, acuminated, and having its nucleus at the lower end.'* — 

 Sowerhy. 



1. P. gracilis, Flem. Brit. Anim. 354. 



Hab, Coldingham Bay^ rare. 



Although I have mot with several examples of this shell, they have all 

 been more or less worn. Shell turrited, with 12 whorls tapering gra- 

 dually ; whorls crossed by seventeen bent obtuse ribs, obsolete at 

 the suture, which is distinctly marked with an impressed and mi- 

 nutely ribbed line. Two elevated lines around the base of the botly- 

 whorl. Aperture oval, white; pillar rounded; canal short. Epi- 

 dermis dark-brown, beneath which the surface is seen to bo spirally 

 striated. Length li'^ths ; breadth i inch. 



Trichotropis. Broderip and Soivcrbt/. 



Shell turbinated and carinatcd externally ; the aperture wide but 

 longitudinal, rather longer than the spire* effuse or obscurely chau- 



