HELIX-PLANISPIRA. 291 



panded ; the brown bauds on the last whorl abruptly terminating at 

 the base of the expanded lip ; margins approaching, joined by a thin 

 callus ; columellar margin slightly dilated, and inclining to be tuber- 

 culated within. 



Alt. 0.55, greater diam. 0.95, lesser 0.70 inch. 



New Georgia, Solomon Is. 



H. novo3-georgiensis Cox, P. Z. S. 1870, p. 170, t. 16, f. 3, 3a. 



I have not seen this species. It may prove to group elsewhere, 

 perhaps in Geotrochus. 



2. Subsection Cristigibba Tapparone Canefri, 1883. 



Cristigibba TAPP. CAN. Annali Mus. Civ. di Genova, xix, 1883, 

 p. 161. Type, H. corniculum H. & J. Planispira in part, of authors. 



With the general fades of Planispira, these shells differ in having 

 a crest or swollen ridge behind the lip, or a strong swelling on the 

 base immediately behind the constriction preceding the lip. The 

 spire is plane, a little immersed or concave in the middle. The 

 group is characteristic of New Guinea. 



Group of H. corniculum. 



Base strongly swollen behind the basal lip ; crest scarcely 

 developed above. Species of New Guinea. 



H. CORNICULUM Hombron & Jacquinot. PL 46, figs. 65, 66, 67. 



Shell umbilicate, suboblong in circumference, depressed, thin, 

 lightly striatulate, shining, whitish, ornamented with one supra- 

 peripheral blackish-band. Spire plane, reddish ; whorls 4, a little 

 convex, rapidly increasing, the last rounded, descending in front, 

 the base substrangulated just behind the lip ; umbilicus narrow, per- 

 forating ; aperture very oblique, ample, subcircular ; peristome 

 broadly expanded, margins approximating, columellar margin short- 

 ly reflexed. Alt. 11, greater diam. 24, lesser 19 mill. (Pfr.) 



Id. of Sorong ; Port Dorey, Dorey Hum, New Guinea; (also Id. 

 of Batjan, according to Wallace). 



H. corniculum H. & J. Voy. an Pole Sud, Atlas t. 5, f. 10-12. 

 ROSSEAU in text of same, p. 13. REEVE Conch. Icon. f. 502. 

 PFR. Monogr. iii, p. 247 ; Conchyl. Cab. p. 425, t. 149, f. 16, 17. 

 TAPPARONE CANEFRI, Ann. Mus. Civ. di Genova, xix, p. 180, 1883 ; 

 xxiv, 1887, p. 143. IT. collis ? TAPP. CAN. Bull. Soc. Zool. Fr. 

 1878, p. 271. 



