HELIX-OBBA. 221 



H. planulata LAM. An. s. Vert., p. 73. FER. Hist., t. 73A, f. 3. 

 PFR. Monogr. Hel. Viv. i, p. 379 ; Conchy lien Cab. p. 105, 1. 14, 

 f. 9, 10. HIDALGO, Journ. de Conchyl. 1887, p. 98, t. 2, f. 5, 6, 

 varieties. Obba planulata BECK. Obbina planulata SEMPER, Rei- 

 sen, etc., p. 126. H. papilionacea VAL., in Humbold & Bonpl., 

 Rec. Obs. Zool. et Anat. Comp. etc., ii, p. 241, t. 56, f. 6 (teste Pfr.). 

 -H. collapsa FER. Prodr., 187? (teste Pfr.). 



The principal character distinguishing this from H. listeri is the 

 less acute carina, and smooth, not malleated, surface. The basal 

 tooth is usually present, but in some specimens it fails. Some shells 

 are beautifully spotted or mottled above ; some are pale, even en- 

 tirely white. A solid, elevated white variety is figured on pi. 68, 

 fig. 85. 



H. CALCAR Martens. PI. 65, figs. 92, 93, 94. 



Shell openly umbilicated, depressed, lenticular, bicarinate, sculp- 

 tured with coarse, oblique decurrent wrinkles; blackish-brown, 

 nearly concolorous; spire nearly plane; whorls 4, a little convex, 

 depressed, the last about equally convex above and beneath, deeply, 

 abruptly descending in front ; aperture subhorizontal, ovate, outer 

 angle acute, brown inside ; peristome reflexed all around, whitish, 

 continuous, scarcely toothed. (Mts.) 



Alt. 9, greater diam. 23, lesser 17 mill. 



Alt. 7, greater diam. 19$ lesser 16 mill. 



Dodinga, Island of Halmaheira, Moluccas. 



H. calcar MTS. Monatsber. Berl. Akad. 1864, p. 525; Ostas. 

 Zool., Landschn., p. 293, t. 17, f. 5. PFR. Monogr. v, p. 404. 



This beautiful snail, says Von Martens, is most nearly allied to 

 H. rota Brod. It differs in having an elevated cord in the place 

 of the upper color-band, so that it may be called bicarinate, as this 

 thread is almost as prominent upon the last whorl as the peripheral 

 keel. All of the rib-like striae continue unbroken over the two 

 keels, whilst in rota only every alternate riblet (usually) is con- 

 tinued upon the peripheral keel. 



The dark interior of the aperture shows this species to belong to 

 the group of H. papilla, listeri, etc., rather than to H. rota. 



2. Group of H. moricandi. 



Basal lip with a strong tooth, marked behind the peristome by a 

 pit. Surface obliquely striate or ribbed, microscopically spirally 



