THE NATURAL HISTORY SURVEY. 53 
As many as half a dozen individuals have been found in a single 
Anodonta. (9668. ) 
Distribution: Western New York, west to Arkansas; Brit- 
ish America south to Texas. 
Geological distribution: Pleistocene. 
Hfabitat: In lakes and rivers where there is little or no 
current. Prefers a muddy bed. 
Remarks: The above description is drawn from a collec- 
tion of over a hundred specimens from various localities. It is 
a very variable species, particularly in its corpulency, but may 
be distinguished from all other species found in this region by 
its large size and general dark green or black color. The 
peculiar undulate character of the umbones will also distinguish 
it from related species. This mud loving species is frequently 
found buried in the mud to the depth of eight inches or more. 
The young are somewhat alate, but lose this character as they 
mature. The rays are very variable; sometimes in the young 
shell they are very strong, grass green in color over a yellowish 
green background, and again appearing very faint on a dark 
green background. The specimens found in the northern re- 
gion show more diversity of form than do those from the south- 
ern and western regions. In the former region the variation is 
from long and narrow to short and stumpy, in this respect ap- 
proaching 4. footiana. 
On October 26, 1897, while the south pond in Lincoln Park 
was being cleaned, a colony of this species was found which 
surpassed anything hitherto found in the area in size and per- 
fection. The epidermis was bright grass green, with fine, 
darker rays; the umbonal region was of a purplish or pink color, 
which in some examples reached far down the shell. Thelines 
of growth on the larger specimens were very coarse and wrinkled 
about the margins of the shell. The larger specimens meas- 
ured as follows: 
Length, 171.00; height, 98.00; breadth, 68.00 mill. 
Tey OOo At 100.00; a 65.00 ' 
ae 165.00; h 96.00; 4 62.00 *' 
ui iG. DOs © 95.00; 4, 59.00 '' 
nd 130.00; ~{, 75.00; ps 54.00 '' 
nf SOO He 71.00; ay 54.00 '' 
Be 14.00%. % 89.00; me 58.00 ‘' 
- 152.00; " 78.00; 4 58.00 
The specimens were found in a black, sticky mud, and were 
buried a foot beneath the surface. 
