222 HELIX-OBBA. 



striated, 2-5 banded. Aperture light inside. No gibbous ridge 

 behind the upper lip. 



This perfectly natural group of species is hard to define, as the 

 forms included are so variable. The basal tooth is rarely obsolete 

 in some forms. 



Key to species. 



Periphery obtuse, moricandi. 



Periphery acutely carinated, 

 Coarsely striate or ribbed, 



Ribbed, carina undulating, rota. 



Coarsely striate, carina even, scrobiculata. 



Very finely striated, lens-shaped, livesayi, basidentata. 



Obliquely wrinkled, plane above, swollen below, bulacanensis. 



H. MORICANDI Sowerby. PL 54, figs. 24, 25, 26, 27. 



Shell umbilicated, convexly conical above, flattened beneath ; 

 delicately obliquely striated, and having most minute nearly obsolete 

 spiral incised lines ; yellowish-white, a little flesh-tinged above, 

 with a single chestnut band above and below, sometimes a nearly 

 obsolete narrow band a short distance below the suture ; periphery 

 rounded or showing the trace of a keel ; whorls 5%. 



The shell is solid, rather smooth. Spire elevated, very obtuse ; 

 whorls 5i, slightly convex, the last abruptly descending in front, 

 swollen on the latter half of the base, deeply grooved behind the 

 basal lip, the groove widening and running into the umbilicus. 

 Aperture subhorizorital, ovate-elliptical, white and banded inside ; 

 peristome not thickened, outer margin very broadly expanded, basal 

 margin reflexed, having a strong tooth in the middle (marked behind 

 the lip by a pit), and usually a second minute denticle on the col- 

 umellar edge. Umbilicus narrow, deep, partly concealed. 



Alt. 16, greater diam. 32, lesser 26 mill. ; alt. 16, diam. 26* mill. 



Islets off northern Mindanao, and Northern and Eastern Mindanao ; 

 Bohol; La Laguna, Isl. of Luzon. 



H. moricandi (SowB. in Cuming's shell list) PFR. in P. Z. S. 1842, 

 p. 86 ; Monogr. i, p. 380 ; Kiister's Conchyl. Cab., p. 62, t. 77, f. 7- 

 9. REEVE, Conch. Icon., f. 58. HIDALGO, Journ. de Conchyl. 

 1887, p. 99. Obbina Moricandi SEMPER Reisen im Archip. Phil. 

 Landmoll., p. 123. 



Semper is in error in referring H. bizonalis Desh. to moricandi as 

 a synonym. The true bizonalis is a West Indian species of the 

 section Caracolus. 



