223 CATALOGUE OF PHANEROPNEUMONA. 
1850, p. 57; Petit, in Journ. Conch. 1850, ii. p. 179; Pfr. 
Pnewm. Mon. p. 319. 
Electrina, Gray, Catal. Cycl. p. 30, 1850. 
The known species may be arranged in the following manner: 
A. Smooth (Electrina, Gray, Cat. Cycl. p.30). §1. N. 1. 
B. With spiral striz or ridges gerne) 
a.Subturbinate . es Sy Di Reg ee 
&. Globose, or conoidal-depressed oo 3) B8h, eee 
¢. Discoidal ’ P ‘ 4, ,, 14-30. 
§ 1. Shell smooth. Electrina, Gray. 
1. STOASTOMA SUCCINEUM. B. M. 
Shell umbilicate, globose-conic, thin, smooth, pellucid, amber- 
coloured; spire conic, rather pointed ; whorls 6, moderately 
convex, the last one excavate beneath ; umbilicus narrow, open ; 
aperture somewhat oblique, semioval; peristome simple, sharp, 
furnished at the base of the columellar margin with a small 
callous tongue, which is horizontally produced into the um- 
bilical keel. Operculum typical. Height 4, greatest breadth 
4+, least br. 3? mill. 
Cyclostoma succineum, Sow. in Proc. Z. S. 1832, p. 32 (Mill. 
Synops. p. 37); Thes. n. SY, p. 108, t. 23, f 18, 19; Pyro Te. 
n. 15, p. 24, t. 3, f. 12-14. 
Cyclostoma australe, Muhlf. MSS. in Anton Verz. p. 54, n. 1946. 
Cyclophorus? succineus, Pfr. in Z. f. Mf. 1847, p. 108, n. 22. 
Stoastoma succineum, Pir. in Z. {..M. 1849, . 115, 1850, p. 59; 
Prneum. Mon. p 319. 
Electrina aaeeen Gray, Catal. Cycloph. p. 30, n. 1. 
Hab. The Polynesian island Opara (H. Cuming). 
§ 2. Shell spirally striated, subturbinate. 
2. SToASTOMA PISUM. B. M. 
Shell perforate, globose-conic, sculptured with very fine, distant, 
spiral ridges, not shining, pale straw-coloured; spire conic, 
pointed; whorls 5, scarcely convex, the last one rounded; 
aperture nearly perpendicular, semioval ; peristome simple, 
scarcely expanded, continuous, with the right margin arcuately 
dilated, basal margin continued into a lamelliform keel, which 
ascends near the perforation, Operce. typical. Height 3, greatest 
breadth 4%, least br. 4 mill. 
