AT I 



We have above expressed the opinion that this group and tin- r. 

 may eventually be removed from Aty*. 



DINI\ II. A: A. Adams, 1854. Shell ovoid, siihtruncate above, 

 longitudinally striated; columella abruptly truncated below, endini: 

 in a tooth-like prominence. Type A. dentifera Ad. 



The next two groups do not appear to offer any differential 

 feature- of importance. All are characterized by the prominent 

 truncation of the columella and the absence of a fold above the 

 vertex. 



RoxanieUa Monterosato, 1884. Shell diaphanous, date-shaped, 

 with spiral plicate sculpture; columella with a thickened sinuosity, 

 simulating a fold. No fold above the vertex. Type A. jeffreysi. 

 This group seems to be synonymous with Dinia. 



Weinknuffia A. Adams. Type A. diaphana Arad. This group 

 offers no tangible differences from 



Subgenus ATYS Montf. 



A. NAUCUM Liune. PI. 28, figs. 11, 12, 13, 14, 15, 16. 



Shell globose-oval, inflated, widest at the middle, solid ; white 

 under a thin buff or chestnut cuticle. Vertex narrowly concave ; 

 body whorl sculptured throughout with engraved spirals, much 

 closer and uneven toward the ends, more spaced or altogether 

 absent in the middle; base concave around the rimate umbilicus. 

 Aperture as long as the shell, the lip rising high above the vertex 

 and angularly plicate there ; columella vertical, angularly plicate 

 or truncated in the middle; outer lip everywhere well curved. 



Alt. 41, diam. 29 mill., often smaller. 



Singapore, Borneo <md r/itlij>phies to Torres Strttit*, e4ward to 

 Viti fs. t westward to Red Se <md M<i<l<"/<> 



Bull'i it'iur.iini L., Syst. Nat. x , p. 726. AD., in Thes. Conch, p. 

 584, pi. 124, f. 107-109. Afu* unnmm S,wi;., Conch. Icon. f. 1. 

 E. A. SMITH, Zool. Coll. Alert, p. 86. Hi: A/.II i:, \\ L. S. N. S. W. 

 ii, p. *4.- MAKII.NS, Mobius' Keise n. Mauritius p. 802. CoOKE, 

 Ann. Mag. N. H. (5), xvii, p. 1'>1. .4^ 'ymbnh(A MONTF., Coneh 

 Syst. ii, p. 343. B. (A.) j'-mtghiosa A. AD., Thes. ii, p. 585, pi. 

 124, f. 110 (not B. ferruyinowi Gmel. p. :54:I2, y<>uiiL r < yr^a); 

 Ann. Mag. N. H. (4), ix, p. :>44. Aty* ornidfn AD., Thes. Conch. 



