ARACHNIDS 



91 



excessive fishing, the state and national governments have 

 attempted to control the numbers taken and have also 

 established hatcheries in which the eggs are hatched and 

 the young protected dur- 

 ing the earliest stages 

 of their development. 



Crustaceans of less 

 economic importance 

 are the barnacles which 

 cling to rocks, wharves, 

 and steamships ; the 

 hermit crabs that live in 

 the shells of mollusks 

 (mol'lusks); and the smaller fresh-water crustaceans such 

 as the Cyclops (sl'klops), Daphnia (daf'ni-a), and Cypris 

 (si'pris) which are barely visible to the unaided eye. 



Figure 87. — Soft-shell Crab. 



Figure 88. — Pill 

 Bug. 



Figure 89. — Cyclops. 



87. Arachnids. — The spiders, scorpions (skor'pi-iins), 

 ticks, and mites are arthropods that are grouped together 

 under the name Arachnida (a-rak'ni-da : Greek, araehne* 

 spider). The spiders and scorpions have eight walking 

 appendages. The forward pinchers of the scorpions arc 

 mouth-parts, and not walking appendages. The harvest- 



