THE FAMILY NAIADES. 



43 



Not being able satisfactorily to make out 

 or arrange tlie following species, 1 have 

 deemed it best simply to insert a list, in their 

 order of habitat. 



EUROPE. 



Unio rubens. Jllenke. 

 Unio rugatus. Menke. 

 Unio gibbus.f Speng. 

 Unio truncalus.f Speng. 



ASIA. 



Unio orien talis. Fer. 



AFRICA. 

 Unio Juliani. Rang. 



NORTH AMERICA. 



Unio Groenlandicus.f SclirO. 

 Unio purpnriatus. Say, 

 Unio oviformis. Con. 

 Unio furvus. Con. 



SOUTH AMERICA. 



Unio nitidens. Fer. 

 Unio obtusus. Fer. 

 Unio preciosus. Fer. 

 Unio psammoica. U'Orh. 

 Unio rhuacoica. D'Orb. 

 Unio Fontainiana. D'Orb. 

 Uniohyla;a. D'Orb. 

 Unio Guaraniana. D^Orb. 



HABITAT UNKNOWN. 



Unio pulchellus. Fer. 

 Unio musivus.f Speng. 



The following Fossil species have been 

 observed in Great Britain : — 



Unio crassiusculus. Soio. 

 Unio concinnus. Sow. 

 Unio uniforrais. Soic. 

 Unio acutus. Sow. 

 Unio Listeri. Sow. 

 Unio Solandri. Sow. 

 Unio porrectus. Sow. 

 Unio compressus. Sow. 

 Unio antiquus. Sow. 

 Unio aduncus. Sow. 

 Unio cordiformis. Sow. 

 Unio crassissimus. Sow. 

 Unio subconstrictus. Sow. 

 Unio hybridus. Sow. 

 Unio Urii. Flem. 

 Unio abductus. Phil. 

 Unio peregriuus. Phil. 



The following have been observed in the 

 United Slates: 



Unio petrosus. Mort. 

 Unio tumiilatis. Mort. 

 Unio terrenus. Mort. 

 Unio saxulum. Mort. 



t On the authority of Ferussac. 



