\fuUuoca from Central Afrtca. 61 



Unto gereti, sp. n. (l*'ig- '»^) 



Shell ovatf, soniewliut tumid, covered with a dark brown 

 silky periostracum ami sculptured with fine rather closely set 

 concentric lines of growth ; umbones slightly eroded, ])romi- 

 nent ; dorsal margin nearly straight ; ventral margin scarcely 

 rounded ; anterior side angled above, obtusely rounded below ; 

 posterior side sloping oblitpiely, sharply rounded below ; 

 lateral teeth short anteriorly, elongat(dy curved posteri<)rly ; 

 anterior cardinal tooth in right valve short, rather square, 

 erect, jagged, incised on the outer side; median cardinal 

 loolh very small ; posterior cardinal rather small, projecting; 

 anterior cardinal in lelt valve bluntly triangular, incised 

 posteriorly ; posterior cardinal bifurcate, thus presenting the 

 appearance of a double tooth ; anterior adductor scars ovate, 

 well impressed ; posterior adductor scars moderately im- 

 pressed ; interior of shell pale bluish white, somewhat 

 iridescent. 



Long. 3t3'5, lat. Gl mm. 



Hah. Lake Tanganyika. 



Unio mashonce, sp. n. (Fig. 10.) 



Shell elongately ovate, rather tumid, covered with a dark 

 blackish-brown pericstracum, sculptured with somewhat 

 coarse and irregular concentric stiite, angled posteriorly ; 

 umbones rather large, prominent though much eroded ; 

 dorsal margin nearly straight; ventral margin almost straight, 

 but very slightly constiicted towards the middle; anterior 

 side rounded above, sloping below ; posterior side produced, 

 bluntly acuminate; anterior lateral teeth veiy short; poste- 

 rior laterals long and coarse ; cardinal teeth in right valve 

 wedge-shaped, solid in left valve, broad, serrated ; anterior 

 adductor scar ovate, moderately deep ; posterior adductor scar 

 narrowly fan-shaped, well impressed ; palleal impression 

 coarse, nacreous, pinkish in colour; outer margins of interior 

 of shell nacreous, bluish white. 



Long. 80, lat. 37*5 mm. 



Hob. A sluit about 16 miles from Eukeldoorn, Mashonaland 

 (Miss Eilti SImr pe-Youiifjs) . 



'J'ype in British Museum. 



Unio shireensis, sp. n. (Fig. 11.) 



Shell ovate, moderately tumid, covered with a pale, rcddisli- 

 browii, rather thin periostracnm. which becomes thicker, 



