584 



PROCEEDINGS OF THE ACADEMY OF 



[Dec, 



Clausilia idioptyx n. sp. PI. XXX, fig. i. 



The shell is quite small, fusiform, brownish-yellow, somewhat trans- 

 lucent; surface glossy, weakly striatulate, nearly smooth, becoming 

 strongly and coarsely striate behind the outer lip. 

 The spire tapers regularly from the penultimate 

 whorl to the obtuse apex. Whorls 8-| to 8^, convex, 

 the last one compressed, tapering to the base. 

 Aperture ovate, with distinct, somewhat retracted 

 sinulus. Peristome reflexed, continuous. Superior 

 lamella very low, obtuse, short, very widely sepa- 

 rated from the spiral lamella, which is minute, and 

 lateral in position. Inferior lamella deeply receding, 

 its base visible as a low fold in an oblique view in 

 the aperture. Within the back it is straight, massive, and ascends 

 obhquely, terminating abruptly on reaching the parietal partition. 

 The subcolumellar lamella emerges very weakly, and in a lateral 

 position it forms an ascending angle, visible by transparence from the 

 outside. Fulcrum and parallel lamella'are visible as two equal, short 

 white folds about as far inward as the lunella. The principal plica 

 runs from near the mouth to a little beyond the lateral line. The 

 upper palatal plica is long, diverging forwardly from the principal 

 plica, its lower end visible in the aperture. The lower palatal plica 



Fig. 12. 



C 



Fig. 13. — Clausilium of C. idiophix. 



is short, parallel to the upper. Its inner end abuts against the lunella, 

 which joins the upper palatal plica near its inner end. There are two 

 distinct sutural plicae and a very weak one between them, as usual 

 (fig. 12). 



Length 9.0, diam. 1.9 mm. 

 7.8, " 1.8 " 



