GASTER0F0D0U8 MOLLUSCA OF BERWICKSHIRE. 31 



The shell is covered with a distinct epidermis, and is very faintly striated 

 spirally at the base. The following description of the animal is from 

 a dead specimen : — Snail completely retractile within the shell, gaste- 

 ropodous, white ; the foot short and broad, with plain margins ; collar 

 narrow, plain. Belongs apparently to the same genus as Bulla trun- 

 cata. 



4. B. truncatat shell subcylindrical, white, smooth, the upper half 

 obsoletely plaited ; apex truncate, umbilicate, the whorls visible in 

 the umbilicus ; aperture narrow-linear above, widened at the base, 

 entire, the margins somewhat thickened, slightly everted, with a 

 plait on the pillar at the base. Length 1 line. Mont. Test. 

 Brit. 223, pi. 7, fig- 5. Flem, Brit. Anim. 293. B. retusa, 

 Wood, Ind. Test. pi. 48, f. 69. 



Hah. Berwick Bay, in sand, very rare. 



The animal is entirely retractile within the shell, and is gasteropodous ; 

 it is of a pure white colour, short, and of a subquadrangular or oblong 

 figure ; (he back covered with a sort of cloak, free on the sides, while 

 the foot extends the whole length of the body. Front wide and trun- 

 cate, binuated in the middle ; eyes two, dorsal, placed at the base of 

 a sort of auricle formed by a fold of the cloak, and reflected backwards; 

 foot entire, truncate anteriorly, rounded behind. Slow in its motions, 

 and issuing from the wide part of the shell. 



5. B. catena, shell oblong, very thin, pellucid, white, striated with 

 chain-like transverse striae ; aperture ampuUaceous, effuse above, 

 the pillar arcuated, plain ; outer lip thin and even ; spire obsolete, 

 consisting of a single involution. Length |th ; breadth ^^^th. 

 Mont. Test. Brit. 215, pi. 7, fig. 7* Fleming in Brewster's 

 Edin. Encyclop. vii. 84. Laskey in Wern. Mem. i. 396. Turt. 

 Brit. Faun. 168. Dillw. Bee. Sh. 478. Wood Ind. Test. pi. 

 18, fig. 15. Turt. Conch. Diet. 24. Brmvn, Conch. Illustr. 

 pi. 38, figs. 33, 34. Bulla punctata, Flem. Brit. Anim. 294. 

 BuUsea catena, Clarke in ZooL Joum. iii. 337* 



Hah. In shell-sand occasionally. 



The stria) are only visible under a good magnifier, when they " appear in- 

 terwoven or formed into links Uke a chain." Mr Clarke has given a 

 description of the animal. 



6. B. pectinatat shell oblong, somewhat widest at the base, milk- 

 white, pellucid, marked with moniliform transverse lines ; aperture 

 ampuUaceous, widening below, where it is remarkably pectinated, 

 effuse at the upper end, the pillar arcuate with a narrow fold ; 

 outer lip thin ; the spire truncate, depressed. Length 2 or 3 

 lines ; breadth more than half the length. Bulla scabra, Mull. 



