514 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



SYNOPSIS OF THE GENERA OP NAIADES. 



r r 



a 



c3 

 >> 



a 



rS 



^H 



4^ 



rr-l 



^ 



fl 



V 



C3 



■w 



4) 



V 







S 



Ph 











s 



OQ 









plil 



^ 



a 





0) 



cS 



(-M 



t>j 





,^3 



a 



45 



a 



OS 





en 





Pi 



(Heterogeriw.) 



Female shell inflated at base in< 

 front of posterior ridge ; maisupinm 

 in hinder part of outer gills. 



'^<: 



I i_ 



(Dif/ence.) 



Female shell inflated behind, 

 above posterior ridge. 



{Mesogenm.) ,■ 



Marsupium a few ovisacs in the < 

 center of outer gills. |^ 



(Ptychogeiue.) 



Marsupium occupying the whole 

 outer gills in a series of folds. 



{Eschatigenw. ) 



Marsupium occupying the outer 

 border of oiiter gills. 



(Diagence.) 



Ovisacs filling the outer gills, 

 running crosswise. 



" Triincilla Rafinesque. 



Micromya Agassiz. 



Lampsilis Rafinesque. 



Pseudospatha Simpson. 



Hyriopsis Conrad. 



Chamherlainia Simpson. 



Cristaria Schumacher. 



Lepidodesma Simpson. 



Pilshryoconcha Simpson. 



Medionidus Simpson. 



Nephronaias Crosse and Fischer. 



Glehula Conrad. 



Ohovaria Rafinesque, 

 - Plagiola Rafinesque. 



Tritogonia Agassiz. 



Cyprogenia Agassiz. 

 Ohliqxaria Rafinesque. 



Ptychobranclms Simpson. 



Dromns Simpson. 



StrophUits Rafinesque. 



Anodonta Bruguiere. 

 Colletopterum Bourguignat. 

 GaiiUotia Servain. 

 Leguminaia Conrad. 

 Lastena Rafinesque. 

 Solenaia Conrad. 

 Gonidea Conrad. 

 Anodonfoides Simpson. 

 Pegias Simpson. 

 Arcidens Simpson. 

 Symphynota Lea. 

 Alasmidonta Say. 

 Hemilastena Agassiz. 

 Margariiana Schumacher.- 

 Unio Retzius. 

 yPleiirohema Rafinesque. 



(Tetragenw.) r g^^^^^ruJa Rafinesque. 



Marsupium filling all four gills, J Schistodesma Simpson, 

 forming smooth pads; beak cavi-| GibiosuJa Sim^ison. 

 ^ties deep. [ Cuneopsis Simpson. 



(Somogena'.) 



Marsui^ium filling the entire 

 outer gills and forming smooth 

 pads. 



