AUBICTTLnxa:. 77 



ture, contracted anteriorly; umbilicus middle-sized, not per- 

 vious, furnished within with an elevated spiral rib ; aperture 

 scarcely oblique, narrow ; parietal plaits two, the upper nodi- 

 form, the other compressed, unequally bifid ; columellar plait 

 transverse; peristome simple, with the margins united by a 

 shining deposit, which is sinuate above ; right margin bidentate ; 

 columellar margin spreading. Length 6f- , breadth 4 mill. 



Plecotrema lirata, H and A. Adams in Proc. Z. S. 1853, p. 121 ; 

 Gen. rec. Moll ii. p. 241. 

 Pfr. Syn. Auric, n. 98 ; 31on. Auric, p. 101. 

 Hab. Moreton Bay, Australia. 



4. Plecotrema bella. 



Shell umbilicate, ovate-conic, solid, scidptured with equal 

 granulate spiral ridges, not shining, of a dirty fulvous colour ; 

 spire produced, gradate, with the apex rather pointed ; whorls 

 seven, girdled with a stronger ridge below the deep suture; 

 last whorl shorter than the spire, acutely crested behind the 

 aperture, keeled at base round the punctiform umbilicus ; aper- 

 ture scarcely oblique ; parietal plaits two, the upper nodiform, 

 the other indistinctly bifid anteriorly, produced externally into 

 the keel ; columellar plait transverse ; peristome continuous, 

 free and slightly expanded all round; right margin bearing 

 within two minute teeth. Length 5, breadth 2f mill. 



Plecotrema bella, H. and A. Adams in Proc. Z. S. 1854, p. 37 ; 

 Gen. rec. Moll. ii. p. 241. 

 Pfr. Syn. Auric, n. 99 ; Mon. Auric, p. 102. 



Hab. Philippine Islands. 



5. Plecotrema decussata. 



Shell subumbilicate, ovate-conic, solid, granularly decussated 

 by spiral furrows and longitudinal striae, slightly shining, 

 brown ; spire conic, with the apex pointed ; whorls seven, rather 

 flat, scarcely distinct, the last a little longer than the spire, 

 somewhat turgid near the suture, attenuated at base, and fur- 

 nished with an elevated crest, which surrounds the umbilical 

 region, pale anteriorly; aperture scarcely oblique, oblong; pa- 

 rietal plaits two, white, the upper perpendicular, the other 

 entering, bifid externally ; columellar plait ascending rather ob- 

 liquelv ; peristome straight ; right margin furnished within with 

 a white callus and two small teeth ; basal margin somewhat 

 truncate ; columellar margin slightly spreading. Length 7, 

 breadth 4 mill. 



