ENTOMiOSTRACA AND PHYLL6pODA. 



275 



what globose. Most of the species are confined to the 

 waters west of the Mississippi River, one however 

 {Esthe'ria . Mexicdna), being found near Cincinnati. 

 Many of them are in appearance not unlike a small 

 clam, or the little fresh-water mollusk, Pisidium, so 

 common almost everywhere. 



15. Art^mia (Fig. 188). 



Artemia occurs only in brine or in the water of salt 

 lakes, although it is not rarely found in the hogsheads 

 of water on railroad 

 bridges or trestles, where 

 the water is made salt to 

 prevent freezing. 



The bodies are slender 

 and pale red, flesh-color, 

 or sometimes greenish. 

 The feet are eleven 

 pairs, beautifully fringed 

 with many long hairs, 

 and bearing the flattened 

 branchial or breathing- 

 plates. When the crea- 

 ture swims on its back, 

 as it habitually does, 

 these feathery feet beat 

 the water in rapid suc- 

 cession, as if a wave 

 of motion were rapidly 

 passing above them. 

 It is a beautiful creature, and one sure to attract at- 

 tention, not only by its graceful motions and prefer- 

 ence for salt water, but by its size, being half an inch 



Fig. 188 — Artemia (a female). 



