ARTHROPODA 2Q5 



the young of a female reach maturity. This is another way of saying that 

 a species is losing ground. Two general methods have been tried to make good the 

 decline in the supply: first, legislation forbidding the taking of animals under the 

 size, which indicates sexual maturity (eight to twelve inches), and forbidding 



FIG. 133. 



FIG. 133. Palcemonetes vulgaris. From Verrill. 



Questions on the figure. Compare the appendages of Palaemonetes with those 

 of the lobster, the crab and Gammarus. What seem to be the functions of the 

 various appendages, so far as position and form may indicate? 



FIG. 134. 



FIG. 134. Gammarus ornatus. From Verrill. 



Questions on the figure. How does this form compare with the lobster and 

 the crabs in differentiation of the segments, in fusion of the segments and in the 

 differentiation of the appendages? 



the capture of females carrying the developing embryos; and, second, attempts on 

 the part of the national government to hatch artificially and care for the moulting 

 young under such conditions that they will be protected from their natural enemies. 

 The problem is not yet solved, and in the meantime another source of food is likely 

 to be destroyed through overfishing. 



The crayfish is prized for food in European countries, but is little used in 

 America as yet. Shrimps, prawns, the "soft-shelled" or blue crab are all of 

 considerable importance in this regard. The smaller Crustacea are a very im- 

 portant element in the food supply of the fishes, both in the fresh waters and in the 

 sea. 



