HELIX. 89 



It should be understood that I do not claim that every species is 

 herein correctly grouped. Many of them I have not seen ; these are 

 interpolated into the sections to which in my judgment they belong. 

 It is often essential to examine specimens, because in descriptions 

 important characters are frequently omitted. 



Three main divisions or supersections may be recognized ; syn- 

 opses of the sections are given 'under each of these divisions. 



Supersection I. THERSITES Pfr. 



Nucleus small, its junction with the aftergrowth not distinct ; 

 whorls keeled ; aperture triangular, the outer lip markedly sinuous 

 just above the peripheral carina. 



Supersection II. HADE A Albers. 



Nucleus small, consisting of less than two whorls ; aperture lunar, 

 outer lip not sinuous; surface striate or decussated, not malleated. 



Supersection III. CA1LEXA Albers. 



Nucleus comparatively large, about one-fifth the diameter of the 

 shell, composed of 2-2* whorls; surface generally malleated or 

 finely wrinkled. 



Supersection I. THERSITES Pfeiffer. 



4 



Under the above name may be grouped two Australasian sections, 

 Thersites and Anoglypta, which agree in being carinated, more or 

 less trochoidal, with small nucleus, 5 to 6 whorls, the last suddenly 

 deflexed below the carina in front. The aperture is subtriangular 

 or irregularly oval, terminations of the peristome distant, its upper 

 portion sinuous just above the termination of the peripheral carina. 



These sections may have, possibly, affinities with Geotrochus or 

 Papuina 



Two sections may be admitted : 



(1) THERSITES Pfr. Upper and lower surface not conspicuously 

 different in sculpture ; peristome expanded, reflexed over and clos- 

 ing the umbilicus. 



(2) ANOGLYPTA Martens. Upper surface spirally ridged and 

 tuberculate, base smooth, polished ; peristome not expanded ; um- 

 bilicus open. 



