Freshicater Shells from Japan. IGl 



parietal callus; labrum acute, projecting in front, rapidly 

 receding- below, sharply angled at each carinal point ot 

 termination ; aperture irregularly quadrate. 



Alt. 1-25, diam. maj. 3'25, diam. min. 2'75 mm. 



Aperture: alt. 1, diam. '75 ram. 



Hab. Lake Biwa, Japan ; on the lower surface of stones 

 near the edge of the lake (^Dr. N. Annandale). 



Choanomphalus japom'cus perstn'atulus, subsp. n. 

 (PI. IX. figs. 1, la, lb, Ic.) 



Shell differing from the typical form in its less swollen spire, 

 strong intercarinal, spiral striation, and less angular labrum, 

 the only marked angle being at its base. 



Alt. 1-5, diam. maj. 3*5, diam. min. 2*75 mm. 



Aperture : alt. 1"25, diam. 1 mm. 



Hab. Lake Biwa, Japan ; on the lower surface of stones 

 near the edge of the lake, in company with the typical form 

 (^Dr. jy. Annandale). 



Planorbis ( Gyraulus) biwaensis, sp. n. 

 (PI. IX. figs. 3, 3 a, 3^ 3 c.) 



Shell subovate, somewhat planulate above, with sunken 

 first whorl, gently rounded at the periphery, pale yellowish 

 brown, thin ; wlioils 3, rapidly increasing, rather distantly 

 and coarsely spirally, and closely, finely, and indistinctly 

 transversely striate, the last whorl laige and rather rapidly 

 descending in front ; suture well impressed ; base of shell 

 angled in the median region; umbilicus wide open, occu- 

 pying about one-fourth of the total diameter of the shell ; 

 columella margin very obliquely descending, slightly curved, 

 diffused above into a restricted parietal callus ; labrum 

 receding below, acute ; aperture ovate. 



Alt. 1'5, diam. maj. 4*75, diam. min. 3'75 mm. 



Aperture: alt. 1"75, diam. 1*75 mm. 



Uab. Lake Biwa, Japan ; on the lower surface of stones 

 near the edge of the lake (Dr. JV. Annandale) . 



Order PROSOBRANCHIA. 



Suborder Pectinibranchiata. 



Family Valvatidse. 



Valvata hiioaensis, sp. n. 

 (PI. IX. figs. 4, 4 a.) 



Shell turbinate, somewhat fiutteued above, pale }-ellowish ; 



