UPPER TENNESSEE DRAINAGE. 579 
41 (French Broad R., Tenn.), made synonyms by Simpson (pp. 122, 
123). There are two specimens (J and 9) in the Walker collection, 
labeled tener (from French Broad, Asheville, N. Car.). They are 
rather thin-shelled, have rays, which are fine, and subcontinuous in 
the male, but somewhat spotted in the female. They undoubtedly 
are a form of E. nebulosa. 
U. stmus Lea, ’38 (Cumberland R., Tenn.) (Simpson, p. 123). 
A male, with strongly developed rays: specimens of this type occur 
frequently, and are practically identical with U. notatus, admitted by 
Simpson as a synonym of nebulosus. 
This tremendous synonym indicates that we have to deal here 
with a very variable species. The variation concerns first of all the 
color pattern of the epidermis (rays). In the second line it is shown 
in the color of the nacre, the shape of the shell, and, of course, some- 
times the females have been made “species”’ for the reason of their 
different shape. It is not excluded that additional synonyms may be 
discovered. 
E. nebulosa belongs in the affinity of E. iris (Lea), ’30, and has 
practically the same anatomy. Indeed, some of its forms are hardly 
distinguishable from £. iris, and it may be that the latter is only the 
western and northwestern representative of it (that of the Ohio 
drainage). Thus it is also explained why iris has been recorded for 
* the upper Tennessee River (Lewis). 
According to my observations, there is only one species of the 
ivis-group in the upper Tennessee region. It is generally an elon- 
gated-elliptical shell, more or less pointed behind in the male, slightly 
dilated and rounded posteriorly in the female, of a yellowish, green- 
ish, or brownish color, covered more or less with rays, which nor- 
mally are well developed, and very often broken up into spots. 
These rays may be fine or wide (in the female, they are often very 
broad and distinct on the dilated part of the shell), may cover all 
of the shell, or only part of it, and may be indistinct or nearly miss- 
ing. The interior of the shell may be white, or of all shades of 
salmon, orange, pink, or purple. 
Although I have tried hard, I have been unable to separate this 
group of forms into species, and it is also impossible for me to dis- 
tinguish local races. It is true that sometimes specimens from a cer- 
