HELIX-OBBA. 223 



The elevated spire, number of whorls (5%, one more than in most 

 species of Obbina), and strong basal tooth (very rarely obsolete), 

 are the prominent characters. The color-pattern is very constant. 

 The periphery is scarcely keeled. 



H. BASIDENTATA Pfeiffer. 



Shell umbilicated, conoid-semiglobose, solid, obliquely striated, 

 white, ornamented with a brown band above and below, and a nar- 

 rower orange band at the suture ; spire convex-conoid, obtuse ; 

 whorls 5, convex, the last carinated, much deflexed in front, the 

 base rather flat. Umbilicus narrow. Aperture horizontal, ellipti- 

 cal ; peristome continuous, reflexed all around, the basal margin 

 armed in the middle with a strong, obtuse tooth. Alt. 11, greater 

 diam. 26, lesser 20 mill. (P/r.) 



East coast of Mindanao ; Islands in the straits of Surigao ; Ubay, 

 Island of Bohol, Philippines. 



H. basidentata PFR. P. Z. S..1856, p. 329 ; Monogr. iv, p. '310. 

 HIDALGO, Journ. de Conchyl. 1888, p. 30, t. 5, f. 9. Obbina basi- 

 dentata SEMPER, Phil. Archip., LandmolL, p. 124 (anatomy). 



I have not seen this form. It seems to be closely allied to H. 

 livesayi. 



H. LIVESAYI Pfeiffer. PI. 56, figs. 72, 73 ; pi. 59, figs. 46, 47. 



Shell narrowly umbilicated, lens-shaped, acutely carinated ; yel- 

 lowish-corneous with two chestnut bands above, one below ; surface 

 delicately obliquely striated, showing under a lens incised spiral 

 lines which are nearly obsolete. Basal lip strongly unidentate in 

 the middle. 



This is a species of about the form of H. scrobiculata but darker 

 colored and far more delicately striated. The surface has some- 

 thing of a silky luster. Above there is a chestnut band bordering 

 the white suture, and another one of a darker shade midway between 

 suture and carina. The carina is white ; the base is more or less ob- 

 viously radiately streaked with light brown, and there is a dark 

 band near the circumference. Spire low-conic ; whorls 5, nearly 

 flat, the last suddenly deflexed in front, constricted behind the 

 basal lip. Aperture subhorizontal, ovate ; outer lip broadly ex- 

 panded, basal lip reflexed, strongly toothed (position of tooth 

 marked by a pit behind the lip), partly concealing the umbilicus. 



Alt. 12, greater diarn. 28 2, lesser 24 mill. 



Zebu and Magtan ; Bohol and Camotes, north of Bohol, Philippines. 



