LYMNZIDZ OF NORTH AMERICA. 123 
In 1871, W. H. Dall published a revision of the Lymneids, and 
under the subfamily Limnzinz recognized the following genera and 
subgenera : 
Genus Limnea Lam. 
Subgenus Radix Mont. 
Subgenus Limnophysa Fitz. 
Subgenus Bulimnea Hald. 
Subgenus Acella Hald. 
Subgenus Pleurolimnea Meek. e 
Subgenus Limnea Lam. 
Genus Amphipeplea Nils. 
Genus Erinna H. and A. Adams. 
In 1872, G. W. Tryon continued Haldeman’s monograph of Lym~ 
nea, recognizing the following groups: 
Genus Limnea Lam. 
Subgenus Auricula Klein. 
Subgenus Bulimnea Hald. 
Subgenus Limnophysa Fitz. 
Subgenus Leptolimnea Swains. 
Subgenus Acella Hald. 
In 1884, the same author arranged the Lymnezids as follows in 
his Structural and Systematic Conchology : 
Genus Limn@a Lam. 
Subgenus Lymnus Montt. 
Subgenus Radix Montf. 
Subgenus Polyrhytis Meek. 
Subgenus Bulimnea Hald. 
Subgenus Limnophysa Fitz. 
Subgenus Leptolimnea Swains. 
Subgenus Acella Hald. 
Subgenus Pleurolimnea Meek. 
Genus Amp/lupeplea Nilsson. 
Genus Erinna H. and A. Adams. 
Genus Lantzia Jouss. 
The treatment of the Lymnzeids in the works of H. and A. Adams, 
Fischer, Gray, Kuster, Clessin, Westerlund and other European writ- 
ers does not differ materially from that cited above. 
In 1905, W. H. Dall revised the Lymnezids of the northern part 
of North America and presented the following synopsis which is, 
without doubt, the best treatment this group has received: 
Genus Lymn@a Lamarck. 
Subgenus Lymnea S. S. 
Section Lymnea S. S. 
Section Bulimnea Haldeman. 
Section Radix Montfort. 
Section Cyclolimnea Dall. 
