48 



uzsrio, 



OVAL. 



Unio merdiger. Walsh. 



Unio argens. Kilst. 



Unio ladius. Kolceil. Schmidt. 



Unio Kurrii. Kuster. 



Unio Retzii. Kuster. 



Unio Nessorynchus. Held. 



Unio tristis. Mbrelet. 



Unio piscinalis. Zeig. JRossm. 



Unio ruhens. Menke. Hossm. 



Unio rugatus. Menhe. Rossm. 



Unio Bandinii. Kust. Rossm. 



Unio Hispanicus. Moquin. Rossm. 



Graells. Bourg. 

 Unio Sandrii. Villa. Rossm. Bourg. 

 Unio destructilis. Villa. 

 Unio Moulinsianus. Dup. Grat. 

 Unio pruinosus. Schmidt. 

 Unio suhdentatus. Zieg. Rossm. 

 Unio vitreus. Stem. 

 Unio Maceer thy anus. Bourg. 

 Unio Byzantinus. Parr. 

 Unio orientalis.^? Parr. 



*Mosiilensis. Lea. 



*Caffer. Kraiiss. 



*Afi.-icarLus. Zea.^ 



Durieui. Pesh. 



Eavoisieri. Pesh.^ 



*Bucklyi. Lea. 



Liebmanni. Phili. 



OVAL. 



*coruscus. Gould. 



*pygmseus. Lea. 



*pusillus. Lea. 



*lucidus. Lea. 



*fuscatus. Lea. 



*perpurpureus. Lea. 



*occultus. Lea. 



*spadiceus. Lea. 



*luridus. Lea. 



*Cumberlandicus. Lea. Chenu. Llan. 



*Jonesii. Lea. 



*lingu8eformis. Lea. 



*SinitMi.* Gray. 



vibex. Con. Han, 



*Muhlfeldianus. Lea. Chenu. Reeve. 

 Han. 



*creperus. Lea. Chenu. Han. 



*glaber. Lea. Chenu. Han. 



*discrepans. Lea. 



^ Yery mucli the form of M. Batavus, Lam., aud may prove to be the same. Voy. de la Mer Morte, 

 par Saulcy, 15th liv., p. T8. 



^ Prof. Krauss informs me that he thinks this is only the young of his Caffer. But not having seen 

 each other's specimens, there remains at least a doubt of it. 



^ This and the previous species are very much like Batavus, and may prove only -well-marked varie- 

 ties. The species in Algeria seems to be very much the same with those of the opposite side of the 

 Mediterranean in France and Spain. The land shells vary little in species, but the species are finer and 

 larger in Algeria. 



* Never having seen this shell, I place it here on the authority of Mr. Gray. — See his figure in Grif- 

 fith's Cuvier, vol. xii. 



