﻿E 



iC 



I O 



rtS 



I I 



{Heterogence.) 



Female shell inflated at base in 

 front of posterior ridge ; marsu- 

 pium in hinder part of outer gills. 



SYNOPSIS OF THK GKNERA OF NAIADES. 



TruncUla Rafmesciue. 



Microuiya Agassiz. 



Lainpsilis Ratinesquc. 



Pricrsoiiia Ortmann. 



Pseudospatha Simpson. 



Hyriupsis Conrad. 



Cluii)tberl(i!)iia Simpson. 



Si III pso Ilia Rochebrune. 



Cris tenia Schumacher. 



Lepidodesina Simpson. 



FUsbryo concha Simpson. 



M cdioiiidus Simpson. 



Nephroiiaias Crosse and Fischer. 



Glebula Conrad. 



Obovaria Ratinesquc. 

 ^ Plagiola Rafincsque. 

 (Digeiia^.) 

 „ 1 11 ■ a . 1 1 t • I I ntogonia Agassiz. 



Female shell inflated behmd, HciHastena Agassiz. 

 above posterior ridge. 



(Mcsogeno!.) f 



. , . . ,, J Cy progenia Agassiz. 



Alarsupium a few ovisacs in thei ObUquaria Rahnesque. 

 center of outer gills. 



(Ptycliogencc.) 



Marsupium occupying the whole 

 outer gills in a series of folds. 



Ptycliobraiichiis Simpson. 



(Eschatigeiia'.) 

 Marsupium occupying the outer Di'oinus Simpson, 

 border of outer gills. 



(Diagciuv.) 

 Ovisacs filling the outer gills, Strophitiis Ratinesque. 

 running crosswise. 



Aiiodonta Bruguiere. 

 Colletopteniui Bourguignat. 

 GabiUotia Servain. 

 Leguininaia Conrad. 

 Lasteita Rafinesque. 

 Soleiiaia Conrad. 

 Gonidca Conrad. 

 Aiiodoiitoidcs Simpson. 

 Strophitus Rafinesque. 

 Pcgias Simpson. 

 Aicideii^ Simpson. 

 Arkansia Ortmann and Walker. 

 Syinphyiiota Lea. 

 Alasniidoiita Say. 

 Margaritaiui Schumacher. 

 I'liio Retzius. 

 Plciiroheiiia Ralinesque. 



(TclragciiCiC.) ( Ouadruhi Rafinesque. 



Marsupium filling all four giUsJ Schi'todesiiius Simpson, 

 forming smooth pads; beak cavi-l Gwbosula Simpson, 

 ties deep '^ Cuneopsis Simpson. 



{Homogena\) 



Marsupium tilling the entire, 

 outer gills and forming smooth 

 pads. 



