AKERA. 527 



truncated at the base. The individual measured nearly two lines 

 and a half in length, and about nine-tenths of a line in breadth. 

 It was stated by Laskey to have been taken near Dunbar, along 

 with numerous other shells which subsequent investigations have 

 proved to be exotic, and reminds one of a sinistral Tornatellina. 



AKERA. O. F. MuLLER. 



Shell very thin, elastic, convolute, ovate, ventricose ; 

 spire truncated; margin of the outer whorl rlisjoined from 

 the suture ; aperture elongate, pyriform, its basal margin 

 rounded ; pillar lip excavated. No operculum. 



Animal elongated, subcylindrical ; not completely in- 

 vesting the shell but covering it in great part by its large 

 lateral lobes ; capital lobe short, truncated in front, subtri- 

 angular and entire behind. No eyes. Tongue armed with 

 a single series of small axile denticles flanked by numerous 

 narrow hamate laterals. According to Loven, a long, 

 slender filiform process of the mantle is lodged in the canal 

 of the spire. The gizzard is set with triangular horny 

 tubercles like that of Aplasia. 



Members of this genus are found in the seas of both 

 northern and southern hemisphere, and within the tropics. 



A. BiJLLATA, Mliller. 



Plate CXIV. D. fig. 4, 5, 6, and (Animal) Plate V. V. fig. 6. 



Ahera bullata, Muller, Zool. Danica, pi. 71, f. 1 to 5. 

 Bulla valuta parva, Chemnitz, Conch. Cab. vol. x. p. 122, pi. 146, f. 1358. 

 „ Ahera, Gmelin, Syst. Nat. p. 3434. — Mont. Test. Brit. vol. i. p. 219. — 



Maton and Rack. Trans. Linn. Soc. vol. viii. p. 125. — Rack. 



Dorset Catalog, p. 43, pi. 22, f. 13. — Turt. Conch. Diction. 



p. 21. — Fleming, Brit. Animals, p. 292. — Brit. Marine Conch. 



p. 139. — DiLLW. Recent Shells, vol. i. p. 482. — Wood, Index 



Testac.pl. 18,f. 23. 

 Bulla Nonoecjica, Bruguiere, Encycl. M^th. Vers, vol. i. p. 377, pi. 360, f. 4. — 



