1901.] NATURAL SCIENCES OF PHILADELPHIA. 



plait." In the specimen before me, the structure is clearly as 

 described above and figured on my plate. When low, ill -developed 

 or " punctiform," these palatal structures are doubtless subject to a 

 somewhat wide range of variation, although the difference between 

 a " punctiform plica with the indication of a lunella," and a 

 " low, ill-defined lunella" occupying the same position, appears 

 greater in the statement than the structure itself. 



Compared with C. perpallida, this species differs in having the 

 principal plica longer, and the superior lamella a little more 

 prominent. The striation is also a trifle coarser, and the form 

 more cylindric, less tapering. These differences do not seem ta 

 me to be of specific importance. 



Clausilia micropeas var. perpallida Pilsbry. PI. XXVIII, figs. 50, 51, 52. 

 0. perpallida PHa., Nautilus, XIV, p. 108 (January, 1901). 



Shell rimate, slenderly fusiform, finely and distinctly striate^ 

 pale corneous. Apex obtuse, the first whorl globose; spire some- 

 what attenuated above. Whorls 9^, convex, the sutures impressed, 

 last whorl but slightly narrower than the penultimate, somewhat 

 compressed. Aperture piriform, slightly oblique, with rather 

 distinct, slightly retracted sinulus. Peristome somewhat thick- 

 ened, reflexed, continuous. Superior lamella vertical, continuous 

 with the spiral lamella, arising at the edge of the parietal lip. 

 Inferior lamella deeply receding, visible only in an oblique view, 

 within straightened and thickened below. Both the spiral and the 

 inferior lamellse penetrate inwardly to a fully ventral position, 

 and are of about equal length; the former becoming very high 

 for a short distance, just within the position of the palatal arma- 

 ture. Subcolumellar lamella is deeply immersed and either not 

 visible within the aperture, or showing the end only in an oblique 

 view. Principal plica less than a half -whorl long, the end visible 

 within the aperture, inner end extending a little beyond a short, 

 slightly curved, or forwardly diverging lateral upper palatal plica; 

 below this, and not connected with it there is a low callous pad 

 representing the lunella; no lower palatal fold. Clausilium long, 

 .slender and parallel-sided, somewhat acuminate toward the apex, 

 tapering to the filament, the sides and apex thin ; in profile seen 

 to be curved, bow-like. 



Length 11.4, diam. 2.6 mm. 



