GASTROCOPTA, EASTERN ASIA. 107 



39. GASTROCOPTA BONINENSIS n. sp. PL 20, figs. 4, 5. 



The shell is rimate, oblong-conic, composed of 5 rather 

 strongly convex whorls, very pale buff, the summit gray. Sur- 

 face scarcely shining, very minutely and densely, irregularly 

 granulose, but scarcely showing a trace of striae. Last whorl 

 flattened over the lower palatal region, having a high crest 

 behind the lip. Angular lamella curving towards the right, 

 its inner end joined to the anterior end of the parietal lamella 

 by a low callous. Parietal lamella nearly behind the angular. 

 The infraparietal lamella is decidedly shorter than the parietal. 

 Columellar lamella strong, horizontal. Four plicae stand 

 upon the strong palatal callous, the lower palatal longest, the 

 upper palatal, basal and suprapalatal being successively 

 smaller. Lip thin, a little expanded. Length 2.17, diam. 

 1.07 mm. 



Ogasawara (Bonin) islands: Minamijima, type loc. ; Chichi- 

 jima (Hirase). 



The angular and parietal lamellae are far more closely 

 united than in G. chiehijimana, and the infraparietal lamella 

 is shorter. It differs from G. armigerella by the lamelliform 

 infraparietal and the less united angular and parietal lamellae. 

 The microscopic granulation is coarser in boninensis and 

 chiehijimana than in armigerella. 



40. GASTROCOPTA ARMIGERELLA (Eeinhardt). PL 20, figs. 7 

 to 11. 



Shell dextral, conic-ovate, rimate, whitish, pellucid, a little 

 shining, smooth. Whorls 5, cylindric, parted by a deep suture, 

 the last a little compressed at base. Aperture rounded- 

 triangular, 7-toothed: two teeth on the parietal wall, one 

 placed in front of the insertion of the outer lip, the other 

 near the columella, smaller, nodule-like and deeply placed; 

 columella bidentate, the upper tooth stronger; three palatal 

 teeth, the uppermost smallest, the lower one large ; they are 

 joined by a callous which is visible externally. Peristome 

 subcontinuous, simple, a little expanded, the right margin in- 

 clined above towards the dilated columella. Length 2%, 

 width 1 mm. (Reinhardt). 



