186 ANNALS OF THE CARNEGIE MUSEUM. 
species of Dysnomia under nos. 13, 14, 15, 18, 19, 20, and 21, we 
observe that they represent types of shells also without representation 
in the Ohio drainage. 
On the other hand, we have in Green River certain Naiades, which 
belong to the Ohio drainage, but are missing in the systems of the 
Cumberland and Tennessee. They are the following: 
Pleurobema clava (doubtful) 5. Micromya lienosa 
2. Aroidens confragosus 6. Ligumia subrostrata 
3. Anodonta suborbiculata 7. Lampsilis siliquoidea 
4. Carunculiana glans (see above) 8. Dysnomia flexuosa (see above) 
Moreover, there are Ohio-species in Green River, of which we 
know, that their center undoubtedly was in the interior Basin, but 
that they subsequently invaded the lower parts of the Cumberland or 
Tennessee (or both), coming evidently from the lower Ohio (compare 
Ortmann, 1925, p. 365). The most striking cases are the following: 
1. Fusconaia ebenus (lower Cumberland and lower Tennessee) 
2. Fusconaia flava and flava trigona (in Cumberland, but not in Tennessee) 
3. Megalonaias gigantea (lower Cumberland and lower Tennessee) 
4. Amblema peruviana (lower Cumberland only) 
5. Quadrula quadrula and var. fragosa (lower Cumberland and_ lower 
Tennessee) 
6. Actinonaias carinata (lower Tennessee only) 
Carunculina parva (Cumberland only) 
8. Lampsilis anodontoides and var. fallaciosa (lower Cumberland and lower 
~ 
Tennessee) 
(Pleurobema clava might also belong here) 
All this tends to show, that Green River has a Naiad-fauna. closely 
resembling that of the Kentucky, Licking, Big Sandy Rivers, and 
that of the Ohio and the interior Basin in general, without any par- 
ticular relationship to that of the Cumberland and Tennessee. A 
good number of peculiar forms existing still in the Cumberland are 
not found to the north of it; and there are others in Green River, 
which find here their southern limit. Thus it is clear, that there is a 
sharp line between the Cumberland andGreen Rivers in southern Kentucky, 
separating two apparently old faunas, the Ohioan and the Cumberlandian. 
There is no gradual transition between these faunas in the sense, that 
their elements gradually disappear, when we go over the several 
river-systems of this region (Cumberland, Green, Kentucky, Licking, 
etc.). This, however, should be the case, if the two faunas had been 
all the time connected in one major drainage-system, as they are now. 
