834 PROCEEDINGS OF THE ACADEMY OF [Dec, 



one-third of a whorl long. The upper palatal plica is very short, and 

 connected with the very oblique and curved lunella. There are two 

 weak sutural plicae. 



Length 9.8, diam. 2.2 mm. 



Length 9.5, diam. 2 mm. 



The clausilium (PI. LVII, figs. 90, 91) is rather short, wider below 

 than above, and strongly curved near the rounded apex; it is abruptly 

 and deeply excised near the filament, as usual. 



Bomayama, Tokunoshima, Osumi. Types No. 87,588, A. N. S. P., 

 from No. 1,201 of Mr. Hirasc's collection. 



This little Clausilia has much in common with the fossil C. dcemono- 

 rum of Kikaiga-shima, but it is somewhat less specialized in having the 

 superior and spiral lamellae continuous. The upper of the two sutural 

 plicae is very w^eak, and in some specimens hardly perceptible. In one 

 opened I saw a very weak lamella inserta. 



Section PARAZAPTYX nov. 



The shell is similar to Zaptyx, except that the inferior and subcolu- 

 mcllar lamellae ascend spirally, as in Metazaptyx; fulcrum and parallel 

 lamella and sutural plicae are absent. The clausilium is wide, tapers 

 strongly to the apex, and is strengthened by a transverse lamellar rib on 

 the convex side. 



The extraordinary clausilium of this group finds no parallel in 

 Asiatic Clausiliidce. Parazaptyx is another of the highly specialized 

 phyla of the Riukiu Islands which give evidence of the ancient origin of 

 these insular faunas. 



In its spirally ascending lamellae and wide clausilium, this Section 

 resembles Metazaptyx, but it is like Hemizaptyx in lacking accessory 

 plicae, and the clausilium is unique. 



Clausilia thaumatopoma n. sp. PI. LVII, figs. 100, 101, 102, 103, 104. 



Shell cylindric below, the upper half tapering and a little attenuated 

 near the apex; brown, the apex pale. Whorls 9, convex, the first two 

 smooth, the second whorl disproportionately wide; third and subse- 

 quent whorls closely, finely and sharply striate, shining, the striation 

 coarser behind the lip. The aperture is trapezoidal-ovate, retracted 

 at the sinulus, not projecting, brown inside ; the peristome is pale-edged, 

 very narrowly reflexed, obtuse but hardly thickened. The superior 

 lamella is subvertical, marginal, rather high, and continuous with the 

 low spiral lamella, which penetrates to the middle of the ventral side. 

 The inferior lamella recedes very deeply, and is not visible in a front 



