HELIX §.21. 109 



anfr. 4 angusti, convexi, confertini radiato-plicati, penultimus 

 prominens, ultimus non descendens , a Jatere subcompressus, 

 subtus valde convexus; umbilicus latus, profundus, margine 

 subangulatus; apertura verticalis, rotundato-Iunaris, allior quam 

 lata; perist. simplex, rectum, marginibus vix convergentibus, 

 callo tenuissimo junctis. — Diam. maj. 5^2, ann. 4^/3, alt. 

 22/3 mill. (Mus. Benson.) 



Helix vorticiaUs Bens. in Ann. and 31ag. 2 d. scr. 1850. Mart. 

 p. 2 16. 



— — Chemn. ed. II. Helix N. 924. t. Ul. f. 28 — 30. 

 Habitat in Promontorio Bonae Spei. (Prope « Three-anchor Bay, 

 Green Point, Camp Ground prope Rondebosch».) 



492. H. biconcava Pfr. 



T. umbilicata, depressa, confertim arcuato-costata , opaca, 

 corneo-lutescens, rufo-strigata ; spira concava; anfr. 4V2 — 5 

 angusti, penultimus convexus, ultimus rotundatus, non descen- 

 dens; umbilicus latus, perspectivus ; apertura subverticalis, 

 altior quam lata, lunaris; perist. simplex, rectum, margine 

 dextro antrorsum subarcuato. — Diam. maj. 5, min. 4^3, alt. 

 2 mill. (Coll. Nr. 214.) 



Helix biconcava Pfr. in Proc Zool. Soc. 1851. 



— — Che?nn. ed. II. Helix N. 1038. t. 155. f. 43 — 47. 

 Habitat in Nova Seelandia (Strange). 



493. H. omicron Pfr. 



T. umbilicata, depressa, utrinque concava, tenuissima, 

 confertissime filoso-plicata, vix nitidula, cornea, rufo obsolete 

 strigata; spira profunde imaiersa; anfr. 4 rapide accrescentes, 

 ultimus magnus, rotundatus, altior quam latus non descen- 

 dens; umbilicus Jaliusculus, conicus; apertura subverticalis, 

 erecto-lunaris ; perist. simplex, reclum, marginibus remotis, 

 vix convergentibus , dextro regulariter arcuato. — Diam. maj. 

 51/4, min. 5, alt. 3 mill. (Coll. Nr. 215.) 



Helix omicron Pfr. in Zeitschr. f. Malak. 1851. p. 128. 



— — Chemn. ed. II. Helix N. 1037. t. 155. f. 13 — 17. 

 Drepanostoma spec. in sched. Sowerbyi. 



Habitat in Australia. 



494. H. zeta Pfr. 



T. lalissime umbilicata, dcpressa, subdiscoidea, solidlus- 

 cula, subconfertim valide plicata, non nitens, pallide flaves- 

 cens. maculis magnis castaneis tessellata; spira plana, medio 

 subimmcrsa; sutura profunda; anfr. Sy^ angustissimi, convexi, 

 turgiduli, ultimus descendens, teretiuscuJus , sublus pJicis sub- 



