J 
960 The American Naturalist. [November, 
Anodonta gigantia Lea. Pond near Shreveport, and in a 
pond in Claiborne Parish. Near Shreveport, in a sequestered 
pond, into whose surface the sunbeams filtered through the 
willows, I made a rich “find ” of a bushel of these Anodontas. 
They were the most beautiful specimens of the genus that I 
have seen, many being a most beautiful but subdued green— 
all as thin as egg-shells. 
Anodonta corpulenta Cooper. Caddo Lake, pond near Shreve- 
port, Bayou Pierre. Not abundant. This Anodonta, with the 
two mentioned just above, have a wonderfully close resem- 
blance, and I would not like to undertake to never get them 
mixed up. I am inclined to believe that they are naturally 
mixed up, and that it is artificial to try to draw sharp lines 
between them. 
Anodonta opaca Lea. Cypress Bayou, Black Lake Bayou, 
Corney Bayou, ponds around Jonesville, Texas; around Grand 
Cane; and I have received some good specimens from south- 
ern Arkansas. The finest specimens were from Jonesville, 
some. being about six inches long, and with an epidermis of a 
beautiful polished mahogany color. This is by far the most 
common of the Anodontas in the section. At one time I had 
two hundred and fifty specimens from one bayou. The varia- 
tion is enormous. The color is from mahogany to green, the 
form may vary from an elongated oval to a short oval, or the 
base may be arcuate, the size may vary in what appears to be 
adult specimens from two to five inches. Yetin spite of all this 
variation with a good suite of specimens, one readily sees that 
it is all the same species, for every intermediate form exists. 
Anodonta suborbiculata Say. Caddo Lake. Very rare. This 
is such a handsome species that one wishes it could be found 
wherever he collects, but he is disappointed in Louisiana. In 
Caddo Lake a few small specimens are found. 
CYRENIDA. 
PISIDIUM. 
Pisidium variable Prime, found in many of the small 
branches. Near Port Caddo, Texas, not far from Cypress 
Bayou, small peat mosses have formed between the bases of 
