RHE = CONCHOLOGISTS? 
BNCHANGE, 35 
green rays. In some respects Unio capax fa- 
vors Unio ventrisosus but it is very distinct, 
however, from that shell. 
7.—Unio coccineus, Hildreth. 
This extremely variable species is found 
only in Edwards Creek, where it is associated 
with Unio rubiginosus, Lea, which it much 
resembles, but as found has a much smoother 
epidermis, is more beautifully rayed, and has 
a beautiful pink nacre. It is a very rare spe- 
cies here and will probably soon be extinct. 
§.— Unto cornutus, Barnes. 
This species is found rather sparingly in the 
Mississippi. I regard it as very constant in its 
characteristics, although I often find individuals 
entirely devoid of rays. It is a tuberculate 
shell, and is usually very finely colored with 
greenish dots and rays. 
g.— Unio crassidens, am. 
This is a very thick and heavy species, with 
dark pink nacre. When young, crassidens is 
beautifully rayed, but the ravs usually become 
obsolete as the shell grows older. It is found 
only in the river and is very rare, as in fifteen 
years’ collecting I have secured but three 
specimens. 
r0.—Unio donacifornis, Lea. 
This small and very handsome species is 
found rather commonly in the river and adjoin- 
ing sloughs. Itis the waleof Unio zig-zag,Lea, 
and as Mr. Lea named it first, it lhes prece- 
dence. Mr. Lea’s types were from Tennessee 
but there is little difference between our shells 
and those in my cabinet from the Cumberland 
River, Tennessee. 
t1.—Unio Dorfeucllianus, Lea. 
Ihave very rarely found this species in the 
river. It is a fine shell and apparently very 
closely allied to Unio pustulosus, Lea, although 
it seems to differ from pzs/u/osus in having a 
darker epidermis and fewer nodules. It also 
differs in oce¢Uinve, which is triancular, while 
pustulosus is subrotund. For some reason I 
have not been able to secure a single specimen 
of it for some three or four years. 
12.—Unio ebenus, Lea. 
This common species has a dark brown 
epidermis and is thick and solid in structure. 
The male is quite different in outline from the 
female. This is the most abundant species in 
the river, equalling in numbers all other species 
of Uniones combined. When collecting in 
deep water it proves very troublesome as it is 
often necessary to handle a vast number of 
this shell in order to obtain other more desirable 
kinds. It is a deep water shell and very slue- 
gish in its movements, preferring soft, gravelly 
Boron: and seems to discard muddy locations 
Ebenus has a white, pearly and very iridescent 
nacre, but occasionally I have found it having 
the nacre tinged with pink. 
13.— Unio ellipsis, Lea. 
This is a very abundant species and takes rank 
next to Unzo ebenus for numbers. It is of a 
smooth, elliptical form, with a dark brown or 
dark green epidermis. Some specimens have 
finely marked rays, while many are (especially 
when adult) entirely devoid of them. This 
species is at times very active and may be found 
near the margin of the Mississippi in great 
numbers, expecially the very young and half- 
grown individuals, 
r4.— Unio elegans, Lea. 
. 
As its name implies, this is one of our mest 
beautiful species. It is only found in the river 
and is rather a rare shell. In its surface mark- 
ing and nacre, it is extremely variable, hardly 
any two shells being found alike. Some spe- 
cimens have a salmon colored nacre, some are 
pink, others are white, shining and very irides- 
cent; others, still, are beautifully rayed, while 
some are found entirely devoid of rays. The 
color of the epidermis is also variable, ranging 
from a light straw, through the various shades 
of green to those of dark and light olive in 
in different specimens. The epidermal mark- 
ings of some are very remarkable, being covered 
with greenish spots, some cuneiform and others 
zig-zag, interrupted by lines of growth. 
To de continued. 
