1 3 14 SPAT HA 



from the abdominal sac ; foot tongue-shaped, thick ; anal and 

 branchial openinj^s separated by a strong- bridge. 6\ rnbcns 

 Lamarck (Troschel). 



Type, Auodonta nibcns Lamarck. 



So far as is known, this entire group is confined to Africa. 

 I have placed the species in two subgenera, Sp'atha typical, in- 

 cluding those forms with smooth or concentrically sculptured 

 shells and Aspathoria of Rourguignat with broken, corrugated 

 sculpture. I know nothing of the soft parts of the latter 

 group, but the shells have the same general arrangement of 

 muscle scars as the true Spathas. In placing species in the 

 two groups of the typical subgenus, it is possible that some 

 errors may have been made, as the groups are founded on the 

 beak sculpture, which is often entirely eroded away. Llnfor- 

 tunately, as with the African Unionido'. there are a large num- 

 ber of species that the writer has not seen. I have, therefore, 

 followed ver}' largel\' the excellent work of Germain, who has 

 had the advantage of access to many of the original types and 

 the large amount of material collected by the recent French 

 expeditions. 



Subgenus Spatha s. s. 



Shell solid, having faint, concentric beak sculpture. 

 Type, Anodonta rnbcns Lamarck. 



Group of SpatJia ruhens. 



Sculpture of the beaks following the growth lines ; shell 

 solid. 



Spatha RUBKN.'^ (Lamarck). 



Shell large, elliptical or elliptic rhoml)oid, usually solid, con- 

 vex to subinflated, inequilateral; beaks moderately full, some- 

 what elevated, nearly smooth or having a few, faint, concen- 

 tric ridges ; posterior ridge low. rounded ; anterior end round- 

 ed ; dorsal outline curved ; base straight or curved ; posterior 

 end usually obliquely subtruncate above, ending in a blunt 

 point below the median line; surface irregularly, concentric- 

 ally striate or sulcatc ; e])idermis coppery, tinted green on the 



