HELICINACEA. 
319 
Helicinacca Pfr. 1847. Zeitschr. f. Malak. p. 151. 
— Pfr, in Chemn. ed. sec. I. 18. p 1. 
Oligyradae Gray 1847. Proc. Zool. Soc. p. 182. 
Plurimi scrip tores Lamarckium sequentes unicum genus 
Belicinam in hac familia admiserunt, donee Cl. Swain son 
(Malac. p. 336) genera nonnulla ab illo separare conatus 
fuerit. — Cl. Gray tandem 1842 genera tria: Helicinam 
(s. 1847 Oligyram ) , Lucidellam et Alcadiam adoptavit; 
praeter ea Trochatella Swains . , definitioni Lamarckianae 
baud congrua, et Stoastoma Adams in familia Helicinaceo- 
rum admittenda videntur. 
L Stoastoma Adams. 
Operculum non spiratum, calcareum, exiliter et irregula- 
riter lamelliferum , extus profunde concavum. Testa globoso- 
conica, depressa vel discoidea; apertura semiovalis vel sub- 
semicircularis , superne et basi angulata; perist. continuum, 
margine dextro rotundato, sinistro stricto, basi carinulam 
spiralem retromittente. 
Stoastoma Adams Monograph of Stoastoma 1849. p. 3. *) 
— Pfr . in Zeitschr. f. Malak. 1849. p. 113. 1850. p. 57. 
— Petit in Journ. Conch. 1850. II p. 179. 
— Adams Contrib. to Conch. N. 8. p. 148. N. 9. p. 158. 
Conspectus specierum. 
A. Laevigatae (Electrina Gray) . . . §. 1. Nr. 1. 
B. Spiraliter striatae vel carinatae, 
a. subturbinatae §.2. — 2 — 7. 
b. globoso- vel conoideo-depressae . . §.3. — 8—13. 
c. discoideae §.4. — 14 — 20. 
§• i. 
1 St. iucdneigm (CycSostouia) Sowerby. 526 
T. umbilicata, globoso-conica, tenuis, laevigata, pellucida, 
succinea; spira conica, acutiuscula; anfr. 6 convexiusculi, 
ultimus subtus excavatus ; umbilicus angustus , pervius ; aper- 
*) Testae apertura accurate semicirculari , ora crassa ; labro producto, 
regulariter curvato, baud reflexo ; labio vix curvato ; operculo calcareo, per- 
concavo, exile et irregulariter lamellifero. (Adams 1. c.) 
