506 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



species are South American. The following list shows the number of 

 species in each genus and the distribution of the genera: 



UNIONIDiE: 



19 Truncilla, United States. 

 3 varieties. 



2 Micromya, United States. 



8 varieties. 

 128 Lampsilis, North America. 

 4 Pseudospatha, Tropical Africa. 

 10 Hyriopsis, Eastern Asia. 



3 Chamberlaiuia, Southeastern Aaia. 

 10 Cristaria, Eastern Asia. 



2 Lepidodesma, Eastern Asia. 



4 Pilsbryoconcha, Sontlieastern Asia. 

 6 iledionidus, United States. 



22 Kephronaias, Mexico, Central Amer- 

 ica, Cuba. 



1 Glebula, United States. 

 9 Obovaria, United States. 



1 variety. 

 8 Plagiohi, North America. 



2 Tritogouia, United States. 



1 variety. 



2 Cyxirogenia^ United States. 



1 variety. 

 1 Obliquaria, United States. 



6 Ptychobranchus, United States. 



8 Strophitus, North America. 



1 variety. 

 55 Anodonta, North America, Eastern 

 Asia, Palearctic. 

 8 varieties. 

 4 Colletopteriim, Southeastern Europe. 



3 Gabillotia, Asia Minor. 



1 varietjr. 



7 Legnminaia, Southern Europe, Asia 



Minor. 



1 variety. 



1 Lastena, United States. 



9 Solenaia, Eastern Asia. 

 1 Gonidea, United States. 



1 Anodontoides, North America. 



2 varieties. 



1 Pegias, United States. 

 1 Arcidens, United States. 

 7 Symphynota, North America. 

 1 variety. 

 13 Alasmidonta, North America. 

 1 Hemilastena, United States. 



6 Margaritana, Circnmboreal. 



145 Unio, North America, Palearctic. 



13 varieties. 

 72 Pleurobema, United States. 



1 variety. 

 99 Quadrula, North Auierica, Eastern 



Asia. 



12 varieties. 



2 Schistodesma, Eastern Asia. 

 1 Gibbosula, Eastern Asia. 



5 Cuneopsis, Eastern Asia. 

 90 Nodularia, Eastern Asia, Asia Minor, 

 Tropical Africa. 

 6 varieties. 



1 Harmandia, Southeastern Asia. 



8 Physunio, Southeastern Asia. 



7 Dalliella, Southeastern Asia. 



11 Grandidieria, Tropical Africa. 

 23 Pseudodon, Eastern Asia. 



1 variety. 

 38 Parreysia, Southeastern Asia, Tropi- 

 cal Africa. 

 8 varieties. 

 5 Ptychorhynchus, Eastern Asia. 

 1 variety. 



3 Virgus, Southeastern Asia. 



2 Ctenodesma, Southeastern Asia. 

 5 Eectidens, Southeastern Asia. 



12 Lamellidens, Southeastern Asia, 



Tropical Africa. 



5 varieties. 



5 Trapezoideus, Southeastern Asia. 

 1 variety. 



3 Arconaia, Eastern Asia. 



1 Pseudavicula, Tropical Africa. 

 1 Arcidopsis, Southeastern Asia. 



9 Tetraplodon, South America. 



1 variety. 

 5 Castalina, South America. 

 1 Callonaia, South America. 



4 Hyria, South America. 



8 Prisodon, South America. 



94 Diplodon, South America, Austral- 

 asia, South Africa. 



6 varieties. 



MUTELIDJE. 



27 Spatha, Tropical Africa. 

 3 varieties. 

 9 Mutela, Tropical Africa^ 



2 Chelidonopsis, Tropical Africa. 

 5 Brazzaja, Tropical Africa. 

 4 Pleiodon, Tropical Africa. 



