1901.] NATURAL SCIENCES OF PHILADELPHIA. 189 



eastern Asia in which the operculum is peculiarly modified, as 

 described above. This subgeneric group I propose to call Idio- 

 poma, the above-described species being the type. 



Ampullaria Winkleyi n. sp. PI. V, figs. 2, 3. 



Shell narrowly umbilicate, globose ; yellowish -olive, uniform or 

 with few or numerous dusky olive spiral bands, the earlier whorls 

 eroded, blackish or ruddy. Surface smooth, somewhat shining, 

 under a strong lens seen to be very densely, microscopically striated 

 spirally, the strise minutely granulose; spire low-conic; sutures 

 impressed, the whorls flattened below them, elsewhere symmetrically 

 convex. Aperture vertical, semi-rotund, narrower above, reddish- 

 tawny and sometimes banded within, becoming white near the lip; 

 peristome a trifle expanded below, white or dirty yellowish, the 

 outer margin equably curved, columella concave, blunt and more 

 or less thickened but not reflexed. parietal callus rather thin, 

 white, thinner within. 



Alt. 58, diam. 50, longest axis of aperture 43 mm. 



Operculum (fig. 3) thick and solid, concave externally, and 

 partially covered with a thin, yellowish -brown cuticle. Inside 

 bluish, with a mica-like gleam, the scar of attachment sunken, the 

 columellar side concentrically striate, the enclosed eminence nar- 

 row, curved and smooth. 



Henzada, Burma. Types No. 76,011. Coll. Acad. Nat. Sci. 

 Phila. 



It is somewhat allied to A. Begini Morlet. 



Donax Bertini n. sp. 



Shell long and narrow, the height contained about 2J times in the 

 length, thin, polished, the color varying from pure white through 

 various tints of pink to purple; beaks situated at the posterior 

 third of the length ; anterior end rounded, posterior end obliquely 

 truncate, rounded at the extremity ; the upper margin anterior to 

 the beaks straight, basal margin but slightly curved ; ridge defining 

 the posterior area rounded. Surface sculptured with slight growth 

 wrinkles, and faintly showing some fine radial striae, which, how- 

 ever, are almost completely obsolete, though plainly visible by 

 looking through the shell, except near the anterior end; the pos- 

 terior area is sculptured with deep oblique grooves, the summits of the 

 intervening ridges cut by finer radial stride. Interior smooth or 



