20 BULLID.E. 



Genus A.TYS, Montfort. 



Eyes none, or sub-cutaneous on the middle of the ce- 

 phalic disk, which is bi-lobed behind. Mantle with the 

 right margin thickened, truncate and reflexed on the 



spire. 



Shell white, solid, colourless, convolute, more or less 

 transversely striated, sometimes covered with a thin epi- 

 dermis ; spire hidden, involute ; aperture narrow behind, 

 dilated in front; columella ending anteriorly in a fold, 

 tooth, or truncature; outer lip posteriorly twisted and 

 produced. 



Syn. Naucum, Sclium. Alicula, Ehrenb. Roxana, 

 Leach. 



Ex. A. Cranchii, Leach, pi. 57, fig. 5. Shell, A. nau- 

 cum, Linnaeus, fig. 5, a. 



The shells in this genus are solid, white, and trans- 

 versely striated ; the inner lip is more or less truncate, 

 and the hind part of the outer lip is produced and spirally 

 contorted. The animals appear to be either totally blind, 

 or to have the eyes sub-cutaneous. The Philippine Is- 

 lands, Ceylon, Australia, and America harbour species of 

 this genus, and one is found in the British Isles. 



Species of Atys. 



alicula, A. Adams. hordacea, A. Adams. 



Cranchii, Leach. naucum, Linn. 



cyliudrica, Helb. obovata, Mke. 



elongata, A. Adams. ovoidea, Quoy and Gain. 



exigua, A.Adams. ovulata, Brocc. 



ferruginosa, Chem, parvula, A. Adams. 



