ACUTE. 59 



oval, or pyriform ; outer lip sharp ; columella smooth, tortuous, 

 truncated, so as to form a notch at its union with the outer lip. 

 — Obs. It is from this notch that we are enabled to distinguish 

 Achatinse from Bulini, which, moreover, generally have a reflected 

 outer lip. The Polyphemi of Montfort have an undulation in 

 the centre of the outer lip. Achatina Virginea, fig. 286. Poly- 

 phemus Grlans, fig. 288. These land shells are found in various 

 parts of the globe, but attain the greatest size and richness of 

 colouring in tropical climates ; particularly in the West India 

 Islands. Mr. Eeeve's monograph contains 129 species. Subu- 

 lina, f. 514, has an elongated spire, it is otherwise an Achatina. 

 PI. 



ACHATINELLA. Swainson, 1828. A genus of shells, difier- 

 ing from Achatina in having the inner edge of the outer lip 

 thickened, and a slight groove near the suture of the spire. 

 Eeeve's monograph contains 45 species. Fig. 287. 



ACHELOIS. Montf. Conilites Achelois. Knorr. Supp. T. .4. 

 fig.l. 



ACICULA. Hisso, 1826. Achatina Acicula, Auct. Cionella, 

 Jefireys. 



ACIONA. Leach, 1815. Scalaeia, Lamarck, 1801. 



ACM^A. Pattelloidea, Gray. Lottia, Gray. 



ACME. Hartmann. A genus formed of Tuebo fuscus, "Walker. 

 Atjeicula lineata, Drap. thus described — " Shell sub-cyHndri- 

 cal, with a blunt tip ; mouth ovate, simple, thin, slightly reflected 

 over the piUar, forming a slight perforation." The animal is. 

 said to resemble a Cyclostoma, but has no operculum. Auricula 

 lineata, Drap. Hist. 57, t, 3, fig. 20, 21. Southern Europe. 



ACTEON. Montf. Toenatella, Lam. 



ACTINOCAI^IAX. Stokes. A genus of Belemnitiform EossUs. 



ACULEATED. Beset with sharp spines, as the margin of Chiton 

 aculeatus, fig. 227. 



ACUMINATED. Terminating in a point, as the apex of Melania 

 subulata, fig. 313. 



ACUS. Humphrey. Teeebea of Lamarck. 



ACUTE. Sharp, pointed, or sharp-edged. 



