CRUSTACEANS 



of food-trough between the "chewing bases" of the gill-feet 

 and passed on toward the mouth by their movements. 



Associates. — Fairy shrimps have few enemies, for their sea- 

 son comes before most animals are active and hungry. Wood 

 frogs and spotted salamanders are laying their eggs then in the 

 same ponds but neither of these groups has yet come into pos- 

 session of its regular appetite. 



Identification. — Fairy shrimps are entomostracans with 

 long (about i inch) distinctly segmented bodies, without a 

 carapace; (Fig. 123) the thoracic appendages are fiat and 

 leaflike. 



closber 



_ FiG._ 123. — Fairy shrimp, Eubranchipus vernalis: I, 

 side view; 2, head of male showing claspers which 

 hold the female. 



A common fairy shrimp, Eubranchipus vernalis.— Like all 



fairy shrimps Eubranchipus constantly swims on its back with 

 its eleven pairs of gill-feet waving above it. Its body is semi- 

 transparent, stout and large, about an inch long. The large 

 frontal appendages or claspers of the male (Fig. 123, 2) are 

 his most conspicuous features. Females can be distinguished 

 by the absence of claspers and by the presence of an egg-sac 

 borne on the ventral side of the body. 



This and allied species are locally abundant in pools during 

 late winter and early spring, but live over the summer as rest- 

 ing eggs. Eastern North America. 



163 



