282 HELTX-PLANISPIRA. 



H. biconvexa MART. Monatsber. Berl. Akad. 1864, p. 526 ; 

 Preuss. Exped. Ostas., Landschn., p. 317, t. 16, f. 13. PFR. Mon. 

 v, p. 404. 



The band-formula is either (12)340 or 10340. One specimen 

 found. 



H. SCHEEPMAKERI Pfeiffer. PI. 55, figs. 48, 49, 40. 



Shell narrowly umbilicated, subdepressed, carinated, slightly stri- 

 atulate, and sculptured with subobsolete, close, very fine spiral lines ; 

 shining, diaphanous white, often banded with brown ; spire plane ; 

 suture superficial ; whorls 4, rapidly increasing, the last very con- 

 vex above, flat beneath, the periphery acutely carinated, descending 

 slightly below the carina in front, distinctly constricted below, not 

 so above ; aperture subhorizontal, ax-shaped, bent upward outward- 

 ly ; peristome subthickened, white, nearly straight above, broadly 

 expanded outwardly, narrowly reflexed below, margins much ap- 

 proaching, the upper incurved, basal arcuate. Alt. 11, diam. 26 

 mill. ; alt. 8, diam. 21 mill. (Martens.) 



Isl. Batjan, Ternate group of the Moluccas. Rather rare on wooded 

 hills. 



H. Scheepmakeri PFR. Zeitschr. f. Mai. 1850, p. 82 ; Conchyl. 

 Cab. p. 351, t. 135, f. 5-7 ; Mon. iii. p. 254. MARTENS, Preuss. 

 Exped. Ostas., Landschn., p. 318. 



The bands are generally one or two, rarely three on the upper 

 surface. Formula 12300 or 02300, or 1(23)00 or 02000 ; sometimes 

 there are none. 



If. aurita, biconvexa and scheepmakeri are closely allied in gen- 

 eral form and especially the aperture. H. aurita has no carina ; 

 H. biconvexa and scheepmakeri are acutely keeled, but the former 

 is about equally convex above and below, whilst scheepmakeri is flat 

 below, very convex above. 



Group of H. endoptycha. 



Spire more or less convex ; last whorl with a pit or oblique de- 

 pression outside ; umbilicated. 



H. ENDOPTYCHA Martens. PI. 45, figs. 32, 33, 34, 35. 



Shell somewhat narrowly umbilicated, depressed, striatulate, some- 

 what shining, brownish-tawny ; spire little convex ; suture quite 

 deep. Whorls 5, the last rounded, with convex base, deeply de- 

 scending in front, having an oblique, descending impression, marked 



