HELIX-PLANISPIKA. 295 



FORM B. Shell relatively smaller, aperture narrower and rotund ; 

 edge of peristome narrow also above and uniformly expanded out- 

 wardly. Color-forms as follows : 



c. Shell with a brown band above, the peristome rosy. Reeve's 

 figure of tortilabia represents this form. 



d. Shell very small for the species, white and bandless, the peri- 

 stome a beautiful rose color. 



e. Shell entirely white, bandless. 



/. Shell blackish all over, the peristome of the same color. 



The H. torticollis LeGuillou (Revue Zool. 1842, p. 140), described 

 from Triton Bay, New Guinea, is probably a synonym. It can 

 only be identified by an examination of the type. See Pfr. Monog. 

 i, p. 388, and Tapparone Canefri, Ann. Mus. Civ. di Genova, xix, 

 p. 173, 1883. 



H. SEMIRASA Mousson. PL 46, figs. 71, 72, 73. 



Shell umbilicated, much depressed, thin, subtly striatulate and 

 beset with very short, not close, hairs ; a little shining, corneous- 

 whitish or white, ornamented with a wide chestnut band above, a 

 narrow one below the middle; spire plane, apex subimmersed ; 

 suture impressed ; whorls 4, little convex, the last depressed-rounded, 

 shortly descending in front, swollen behind the aperture, on the 

 base rather flattened, subconstricted in front ; umbilicus moderate 

 (about one-seventh the diameter of the shell), conical. Aperture 

 very oblique, lunate-subcircular ; peristome simple, rosy, margins 

 converging, the upper narrowly expanded, basal narrowly reflexed, 

 dilated in a triangular plate at the insertion. 



Alt. 7, greater diam. 19, lesser 16 mill. (Pfr.) 



My sol and Aru Is., near New Guinea. 



H. semirasa (Mouss. in coll.) MARTENS, Preuss. Exped. Ostas., 

 Landschn., p. 392. PFR. Novit. Conch, iv, p. 38, t. 117, f. 4-6. 

 TAPP. CAN. Ann. Mus. Civ. Genova, xix, p. 173, 1883. H. moluc- 

 censis PFR. Zeitschr. f. Mai. 1850, p. 84 ; Mon. iii, p. 245 ; Conchyl. 

 Cab., p. 352, t. 135, f. 10, 11. 



The name moluccensis Pfr. has priority, but has been changed by 

 Martens, because the species is not from the Moluccas, but belongs 

 to the Papuan fauna. It is closely allied to H. tortilabia. 



H. PLAGIOCHEILA Tapparone Canefri. PL 52, figs. 82, 83, 84. 



Shell umbilicated, discoidal, rather thin, pellucid, obliquely 

 striatulate and obsoletely impressed-punctate ; covered with a gray- 



