112 GUDE : NEW AND UNFIGURED SPECIES OF PLECTOPYLIS. 



and below that, but more anteriorly, another stronger elongated 

 denticle. 



Major diam. i6'5, minor i4"5 ; alt. 8 millim. 



Hah. — Island Bah-Mung. 



The shell figured is Dr. von ^Ollendorff's type specimen. 



P. Jiirsuta, in outward appearance resembles P. villeilanji, but is a 

 trifle smaller, and differs in the umbilicus, which is not so much excav- 

 ated and not carinated as in that species. The parietal fold at the 

 aperture in P. rllleilanji is shorter, more raised, and more oblique. 

 The principal difference, however, is in the parietal armature, as a 

 comparison of the figures will show. In this character P. hirsufa is 

 more allied to P. haraiji, the posterior parietal plate of the latter, 

 however, gives off at the upper extremity a short ridge which is wanting 

 in P. liirmta, and the anterior parietal fold in P. hava;// is straight, 

 oblique, and considerably stronger and longer. In the palatal armature 

 these two species are also closely allied, but in the present species the 

 fifth fold has the lower extremity bifurcated, a feature not found in its 

 ally, while the sixth fold of P. havaiji is in P. lursufa reduced to a 

 strong denticle. Figs. la — ic give three different views of the entire 

 shell, fig. id shows part of the exterior behind the peristome, enlarged. 

 In fig. le the parietal, and in fig. if the palatal armature is shown 

 diagrammaticallv. 



Pleetopylis (Sinieola) fruhstorferi, Mlidff. Figs. 2a— 2e. 



PlectopijJ is (Sinieola) fruJixf (Iff eri, Mlidff. : Tom. cit. p. 114. 



Shell dextral, discoid, widely umbilicated, thin, fragile, dark cor- 

 neous, dull, finely striated. Spire flattened, apex obtuse, suture 

 slightly impressed. Whorls 6, rounded, increasing slowly, the last a 

 little dilated towards the mouth, scarcely descending in front. Aper- 

 ture oblique, subrotundate. Peristome fuscous, slightly thickened 

 and shortly reflected; margins approaching, united by a very slight 

 flexuous ridge on the parietal callus, with a slight oblique free entering 

 fold. Umbilicus wide, rather shallow. Parietal armature composed 

 of a strong oblique crescent-shaped plate with two short, free, hori- 

 zontal folds in front. Palatal armature composed of: first, two short 

 elongated denticles in a line near the suture ; next, four short, oblique, 

 slightly curved folds, attenuated and slightly notched posteriorly ; 

 and finally near the lower suture a short horizontal fold with a .slight 

 denticle above its posterior extremity. 



Major diam. i2"5, minor 11; alt. 5 millim. 



Ilab. — Kebao, 



