
FOOD AND FEEDING 

caying vegetation, organic offal and small infusoria. They are the best 
food for the goldfish. It has been noticed that the tiny newly hatched 
alevin will follow Daphnia to feed upon the young as they are released 
from the brood pouch of the female. The most generally distributed 
forms are Daphnia levis, D. pellucida, D. pulex, Daphnella branchyura, 
Ceriodaphnia pulchella and Sida crystallina. 
PotypHemus. Fig. 67. One species of Polyphemus is quite Beer 
ally present in still and stagnant water. This is P. . 
pedeculus, of which the body is of most grotesque form, 
owing to the peculiar humplike brood pouch. It is 
smaller than the Daphnia, about .65 to 1 millimeter in 
length. 
Lerropora. Fig. 68. One form of Leptodora Ws? 
is quite generally present in larger bodies of freshwater, FIG. 67. Polyphemus 
and may be taken on the surface on bright days. The Re oe ae 
body is long and is covered by a faintly segmented carapace. ‘There are 
two long swimming legs and the very long antenne branch at the ends and 
are furnished with swimming bristles. 
L. hyalina is the most generally dis- 
tributed form. Its length is about 
I to 1.§ millimeters. 
Sus-Orber Ostracopa. Com- 
é pressed body small, indistinctly seg- 
FIG. 68. Leptodora hyalina. Greatly enlarged. | mented, in a bivalve shell, five pairs 
of feet adopted to swimming and creeping. The freshwater form is Cyprvs. 
Cypris. Fig. 69. Several species are very generally distributed and 
may be taken from almost every water which contains the other entomos- 
traca. The body is unsegmented and is enclosed in a carapace articulated 
at the dorsal edge to form a bivalve shell. At 


the anterior end is a median eye, and there are 
seven pairs of swimming appendages. Its size is 
1 to 1.5 millimeters, and its movements are slow 
and leisurely either in swimming or in crawling 
over the bottom. The young are developed in 
the brood pouch but are expelled in the larvel FIG. 69. Cypris virens. 
Greatly enlarged. 

condition. This Crustacean propagates even more 
abundantly than the Daphnia, and will prey upon the eggs and embrios 
of fishes, a number of them may attack an alevin, fastening themselves 
to its surface and devouring it in spite of efforts to free itself. Goldfishes 
eagerly eat the Cypris. The generally distributed forms are Cypris-virens, 
C. pubera, C. pellucida, C. fusca and C. ornata. 
120 
