ALBERSIA-THERSITES. 125 



External anatomy and genitalia unknown. 



Jaw arcuate, solid, with 6 strong ribs, denticulating the margins, 

 and grouped on the median part of the jaw, the ends free from ribs 

 (pi. 34, fig. 8, A. zonulata). The jaw of A. pubicepa also is 

 stated by von Martens to be ribbed. 



Radula as in Chloritis, etc. ; the central and inner lateral teeth 

 having a single cusp shorter than the basal plates, the side cusps 

 represented by slight lateral extensions of the central cusp. Outer 

 laterals having a long, oblique cusp, which becomes bifid on the 

 marginals (mesocone+entocone), and on the outer teeth a small 

 ectocone appears (pi. 34, fig. 9, A. zonulata). 



This group should perhaps be considered a subgenus of Chloritis, 

 but it differs in the thin, capacious form of the shell and the 

 Cochlostyla-like columella. No just estimate of the rank or posi- 

 tion of the group can be made until the soft anatomy is investigated. 

 The jaw and teeth offer no differences from those of Chloritis, 

 Thersites, etc. Distribution, New Guinea and Moluccas. 



A. granulata Q. & G., vii, 90. A. zonulata Fer., vii, 91. 

 A. pubicepa v. Mart., vii, 90. lemniscata Less. 



tortistylis Mouss. v. recluziana Le Guill. 



A.pseudocorasiaStrub., viii, 293. A. tenuis Pfr., vii, 91. 



Genus THERSITES Pfr., 1855. 



Thersites Pfr., 1855, plus Hadra Alb., 1860, plus Badistes Gld., 

 1862, plus Sphcerospira Morch, 1867, plus Xanthomelon v. Mart., 

 1860, plus Rhagada Alb., 1860, plus Qlyptorhagada Pils., 1890. 



Shell narrowly umbilicate or imperforate, varying from globular 

 to trochoidal or thick lens-shaped and keeled, usually solid. 

 Whorls 5 or 6, the apex smooth, never granulated or punctate in reg- 

 ular quincunx ; last whorl varying from smooth to rudely wrinkled, 

 generally densely granulated or roughened microscopically, but 

 never bearing spaced liairs or hair-scars in regular oblique series. 

 Aperture moderately oblique, the outer lip expanded (except in 

 Glyptorhagada), basal lip reflexed, dilated at the columellar insert- 

 ion, the ends of the lip rather remote. Type T. richmondiana, pi. 

 29, fig. 8. (See also all figures on pi. 27). 



Animal having the general features of that of Camcena, Chloritis, 

 etc. ; the sole undivided and without grooves above its margin ; 

 back with one or few grooves from mantle to head ; sides irregularly 



