
FOOD AND FEEDING 

Sus-Orpver Coporopa. Body small, distinctly segmented, the fore- 
most segment fused with the head; antenne, mandables and maxilla well 
developed, six pairs of swimming feet in the free-swimming freshwater 
forms, which consist of the Cyclops and Canthocamptus. 
Cyctors. Fig. 70. Ten or twelve closely allied forms abound in 
still and stagnant water. Their size is 1 to 1.5 millimeter. The segmen- 
tation of the body is perfect, the Crustacean being 
covered with a carapace of which the first segment 
is fused with the head. Two long antennz are 
present and but a single eye. The swimming 
legs are attaches to the thorax, and the lengthen- 
ed abdomen is provided with caudal appendages. 
Their food is organic substances, infusoria and 

alge, and their movements are steady and regular 
FIG. 70—Cyclops thomas, aS though propelled by driving wheels. The most 
oe generally distributed are C. thomasi, C. gyrinus, C. 
agilis, C. edax, C. modestas, C. ater and C. viridis. Canthocamptus is rare in 
the Eastern and Middle states and occasionally occurs as an unrecognized 
species. 
These Copopods possess extraordinary fecundity. In the winter they 
seek the bottom and hibernate, but when the water reaches a temperature 
of 45° to 50° F. they revive, their increase being greatest at 65° to 70° F.; 
when the female every two days develops two egg sacs or external uteri, 
wherein 16 to 32 eggs are hatched. In two days these become detached, 
fall to the bottom where the young, almost globular cyclops, having four 
legs but no tail, undergo a molting in about 15 days, when the other feet 
and the tail form. In another 15 days they mature and reproduce. Car- 
bonate of lime is necessary in the formation of their shells. They thrive 
in water infused with vegetal matter in decomposition, but as it does not 
contract any odor of decomposition it is probable that they live on the 
infusoria. Potamogeton, Ceratophyllum and Fountain cress, upon which 
alge and voucheria will form are usually present to sustain the infusoria. 
Young goldfishes usually reject Cyclops when they can obtain Daphnia. 
It has also been observed that some species of Cyclops feed upon fish spawn 
and will attack very young fishes. 
Matocostraca. These highly organized Crustacea have the thorax 
of eight and the abdomen of seven segments. The sub-order Amphipoda 
are shrimplike forms with stalked eyes; the /sspoda have depressed or flat- 
tened bodies and gills borne on the abdomenal appendages; and the 
Decapoda have the thoracic segments united with the head in a carapace, 
12I 
