52 



BRANCH ARTHROPODA. 



Fm. 78. 



ORDER SIPHONOSTQMATA (si foil o stom'a ta). 



The Fish-louse also comes from the 

 egg as a Nauplius. The adult females 

 are provided with a grapple, by means 

 of which they become attached to their 

 hosts, losing finally, in their parasitic 

 life, all trace of segmentation, becom- 

 ing mere bags for retaining the juices 

 of their host, and nourishing the large 

 sacs of eggs, which are seen attached 

 at the sides. 



E 



Lern <x, o ?' ma ra di a' ta. 

 Fish-louse. R, Grapple, 

 by means of which it 

 holds to its host. S, Neck. 

 B, Body. E, Egg-masses. 



ORDER PHYLLOPODA (fll 6p'6 da). 



The Fresh-water Shrimps are the 

 most familiar representatives of the Phyllopod inro pod) 

 Crustaceans. These are found in the 

 spring, swimming about on their 



Fn;. 79 



FIG. .so. 



Branch' i pm verna'lis. Fresh-water Shrimp, as it swims 

 in the water. B, Gills. 7, Intestines. 77, Elongated heart. 

 (Enlarged.) 



backs in the pools of melted snow. 

 Cones' Shrimp is found in the small 

 pools of the western prairies.* 



Lep i dti'rus cmies'\ i. 



* The eggs of many Phyllopods have the power of enduring desiccation, the 

 pools in which they are deposited drying up in the summer months. Eggs de- 

 prived of water for years, have been known to produce young. 



