494 ; MEMOIRS OF THE CARNEGIE MUSEUM 
highly esteemed European forms, but I know from my own experience that, as 
regards quality, the former are not inferior to the latter. Young specimens (and 
chiefly soft shells) may be fried in butter and eaten shell and all, while the abdom- 
inal muscles of older ones, when boiled in water, are very good. 
Of course, it is hard to create a taste for crawfishes among the masses, but I do 
believe that it would be worth while to try. Crawfishes are so abundant in certain 
parts of the larger rivers, C. limosus in the Delaware, and OC. obscwrus in the Ohio 
drainage, that it is easy to get any amount of them. It also would not be difficult 
to raise them, for instance in ponds, and to supply the market regularly and judi- 
ciously. And further, I do not see, why the “tails” (abdomen) could not be used 
for canning, exactly like the tails of shrimps and prawns. 
Beyond this, crawfishes are used only as bait by fishermen. ‘This use is quite 
general, and crawfishes form an important part of the fisherman’s outfit especially in 
western Pennsylvania. ‘They are most valuable in fishing for Black Bass (Microp- 
terus), since these fishes seem to be very partial to this bait. 
3. Crawfishes as scavengers. Thew food. Their enemies. 
The indirect economic value of crawfishes is best expressed by saying that they are 
scavengers, as decapod crustaceans in general. They dispose effectively and quickly 
of any decayed matter, animal or vegetable, coming within their reach. They also 
eat living creatures. This was known previously. Abbott (1873, p. 83) calls them 
(C. limosus and bartoni) “ omnivorous,” and “scavengers,” and says that they eat 
water-weeds, and seize young Cyprinoid fishes. Andrews (1904, p. 175) fed C. 
limosus in the laboratory on raw and cooked meat, raw eggs, pieces of earthworms, 
and on Chara and Hydrodictyon. Williamson (1901, p. 12) reports that C. monon- 
galensis was caught in traps baited with raisin and oatmeal. I used for my speci- 
mens in the laboratory all kinds of meat, and since I am especially fond of smoked 
sausage, I let them often partake of it when I had it for lunch. They also eat earth- 
worms and green vegetable matter, for instance seedlings of several weeds (Galin- 
soga, and Rumex acetosella), grass, and water-weeds (Vallisneria). In nature they are 
often found at carcasses and other animal refuse lying in the water. They eat in- 
sects. For instance I have seen C. bartoni taking grasshoppers used as bait while 
fishing for trout (Tub Mill Run, Ross Furnace, Westmoreland County). In the 
case of the chimney-builders vegetable matter seems to be largely resorted to, not 
only fresh plants, but also decaying vegetation being used. In digging them out of 
their holes I repeatedly found masses of decaying leaves and the like lodged in some 
side branch of the hole in such a position that they could not have fallen in acci- 
