AMPELITA. 155 



columella, as well as the smooth jaw, are characters which Pyrochi- 

 lus shares with Acavus ; but in the present group the embryonic 

 shell is not differentiated or demarked from the post-natal portion, 

 as is the oblong, globose nuclear shell of Acavus ; and the young are 

 acutely keeled, as in Camcena. 



The few species are from Halmahera and Batjan, Moluccas. 



P. lampas Miill., vi, 194. P. pyrostoma Fer., vi, 194. 



carina Wood. v. bucculenta Tap.-Can., vi, 195 



magnet Schum. v. extincta Tap.-Can., vi, 195. 



gigas Swains. P. xauthostoma Herk., vi, 197. 



P. sulcocinctus Mart., vi, 196. 



Genus AMPELITA Beck, 1837. 



Ampelita BECK, Index Moll. p. 30 (proposed for zodiaca, xystera, 

 labrella, lancula, madagascariensis, clotho, alecto^). ALBERS, Die 

 Hel., 2d edit, p. 163. PILSBRY, Man. Conch., vi, p. 16. 



Shell depressed, solid and opaque, varying from broadly openly 

 umbilicated to perforate ; spire low, convex ; the periphery rounded 

 or keeled. Surface smoothish, sometimes malleated. Aperture 

 very oblique, oblong-truncate ; lip expanded above, reflexed below, 

 toothless. Type A. xystera Val. (see pi. 41, figs. 31, 32, 33, A. hemi- 

 oxia). 



Foot indistinctly tripartite beneath, the upper surface evenly tuber- 

 culate, without longitudinal grooves on back or tail. Mantle-edge 

 unusually thick, the right body-lappet very small, left lappet situ- 

 ated far to the left, and very low. 



Jaw (pi. 51, fig. 5, A. xystera} rather widely arcuate, smooth, its 

 anterior surface totally lacking ribs or striae, very minutely denticu- 

 late in the middle of the cutting edge. The jaw figured measures 

 1.5 mill. wide. 



Radula (pi. 51, fig. 4, A. xystera. PI. 49, fig. 25, A. sepulchralis) 

 composed of very broadly V-shaped, transverse rows ; all of the teeth 

 unicuspid. Cusps of all teeth wide and rounded, the centrals and 

 laterals having the basal plates longer than the cusps, marginals 

 with shorter basal plates, as usual. 



Genitalia without accessory organs. Penis stout and short, the 

 retractor and vas deferens inserted at its apex ; walls of penis cavity 

 corrugated, the vas deferens entering through a small papilla (pi. 

 51, fig. 6). Externally, the lower course of the vas deferens is closely 



