276 ATYS. 



sometimes closely appressed and sometimes loose with a chink be- 

 hind it, but there is no anterior pit ; the shell is more slender for- 

 ward than behind, the bevelling is more marked in some specimens 

 than in others a fragment from off Havana, if conspecific, as seems 

 likely, indicates that it reaches a much larger size than the de- 

 scribed specimens. Lon. of shell and aperture, 6'5. Max. lat. of 

 shell, 3'4, of aperture 1-75 mill. ; lat. of aperture 0'5 mill. (Dall). 



0/Bahia Honda, Cuba, 220 fms. ; Near Santa Cruz, 38 fms. 

 Atys f sandersoni DALL., Bull. M. C. Z. ix, p. 99, 1881 ; Blake 

 Gastr. p. 54, pi. 17, f. 7. 



A. CASTA Carpenter. Unfigurcd. 



Shell elongated, thin, subdiaphanous. whitish ; a little more swol- 

 len anteriorly ; spire concealed, lacunate, in adult shells hardly 

 umbilicated ; columella a little intorted, effuse ; umbilicus small ; 

 lip produced posteriorly, obtusely angulated ; entire surface subtly 

 spirally striatulate. Alt. .4, diam. '18 inch (Cjpr.). 



Cape St. Lucas. 



t Atys casta CPR., Ann. Mag. N. H. (3), xiii, p. 314, 1864 ; Moll. 

 Western N. A. p. 104, 212. 



On the confines of the genus related to Cylichna ( Cpr.'). 



Subgenus DINIA H. & A. Ads., 1854. 



A. DENTIFERA A. Adams. PI. 27, fig. 81. 



Shell ovoid, posteriorly subtruncated, anteriorly produced, horny, 

 pellucid, longitudinally sulcated ; outer lip simple, acute ; inner lip 

 anteriorly strongly truncated, ending in a dentiform plate (Ad.~). 



Lord Hood's Island (Cuming) ; Suez (Cooke) ; Mauritius (Mart.); 

 LevuJca, Fiji (Challenger). 



Bulla (Atys) dentifera AD., Thes. p. 588, pi. 125, f. 124. .1. den- 

 iifera SOWB., C. Icon. t. 2, f. 13. COOKE, Ann. Mag. N. H. (5), 

 xvii, p. 133. MARTENS, Meeres-fauna Maurit. p. 303. Atys (Di~ 

 nia) dentifera ADS., Genera, ii, p. 21. WATSON, Chall. Kep. p. 

 641. 



A. MONODONTA A. Adams. PI. 28, fig. 17. 



Shell subcylindrical, posteriorly subtruncated, anteriorly pro- 

 duced, solid, opaque, longitudinally grooved ; outer lip indexed in 

 the middle ; inner lip strongly truncated anteriorly, and ending in 

 a dentiform plate (Ad.'). 



Shores of Borneo (Cuming). 



