Mollusca from Central Africa. 59 



Subulina maringoensis, sp. n. (Fig* 3.) 



Shell subulate, shining, thin, yellowish horn-colour ; 

 whorls 9, somewhat convex, sculptured with fine transverse 

 striae, which are more marked immediately below the sutures ; 

 sutures deeply impressed, crenellate ; columella arched, 

 curved, obliquely truncate; labrum acute ; aperture inversely 

 auriform. 



Alt. 14, diam. maj. 3*5 mm. 



Aperture: alt. 2*25, diam. 1*25 mm. 



Hah. Maringo Plateaux, Belgian Congo. 



The species may be compared with S. octona, Linn., but is 

 much less blunt at the apex and has considerably more convex 

 whorls. 



Limnaa anceyana, sp. n. (Fig. 4.) 



Shell fusiformly ovate, thin, semitransparent, pale yellowish 

 horn-colour ; whorls 5, rapidly increasing in size, the last 

 somewhat laterally contracted, marked irregularly with lines 

 of growth; sutures well impressed; columella descending 

 obliquely, twisted and diffused into a very thin callus which 

 reaches the lip above ; labrum acute ; aperture elongately 

 ovate. 



Alt. 19, diam. maj. 7, diam. min. 5 mm. 



Aperture : alt. 9, diam. 5 mm. 



Hub. Maringo River, Belgian Congo. 



Unio angoniensis, sp. n. (Fig. 5.) 



Shell ovate, slightly angled posteriorly, covered with a 

 blackish-brown laminiferous periostracum ; sculptured with 

 closely set, irregular, concentric growth-lines, and posteriorly 

 with curved, transverse, interrupted, slightly nodulous riblets; 

 umbones much eroded, rather large, moderately prominent; 

 dorsal margin somewhat ascending, scarcely arched ; ventral 

 margin nearly straight ; anterior side abruptly rounded ; 

 posterior side sloping above, then angled and descending 

 sharply below ; lateral teeth elongate, curved ; cardinal tooth 

 in right valve elongate, erect and jagged anteriorly, partially 

 cleft posteriorly ; cardinal tooth in left valve somewhat 

 triangular, broad, tuberculous in the middle, erect and jagoed 

 at the sides; anterior adductor scars deeply impressed, ovate ; 

 posterior adductor scars light ; interior of shell nacreous, pink 

 anteriorly, livid bluish posteriorly. 



Long. 26, lat. '69 mm. 



Hab. Angoniland, British Central Africa, to the south of 

 Lake Nyassa. 



