CEAES JJfTD SHKIMP8. 205 



" He hung a bottle on each side 

 To keep his balance true," 



our little natatory harlequin " carries weight." But 

 these bags are filled with eggs, a temporary provision 

 for their due and proper exposure to the water, while 

 yet they are protected from enemies. They are devel- 

 oped only at certain seasons, when the eggs having at- 

 tained a given amount of maturity in the ovary, are 

 transferred through the exceedingly slender tube into 

 these sacs, and are there carried about by the mother 

 until the young are hatched, when the curious recep- 

 tacles, being no longer needed, are thrown off, and 

 speedily decay. 



Here is a second foi-m. It is named Zynceus, and 

 is nearly as common as the Cydqps in our stagnant 

 pools. Essentially its structure is the same, but it has 

 this peculiarity, that its body is enclosed within a trans- 

 parent shell, which is thin and flattened sidewise, and 

 .through whose walls all the movements and functions 

 of its parts are distinctly visible. The shell is broadly 

 ovate in outline, comes to a sharp edge above, but is 

 open all along the lower half of its circumference — as 

 if two watch-glasses had been soldered together, edge 

 to edge, and then a portion of the semicircumference 

 had been ground away, so as to leave a thin but long 

 entrance. Through this narrow orifice the limbs are 

 protmded for locomotion, and through it the surrounding 

 water finds its way in currents, bringing oxygen to be 

 respired and food to be devoured. 



The translucent shell descends in front into a sharp 

 long beak, below whick are seen the organs of the 

 mouth, two pairs of foot-jaws, beset with fine bristles. 

 At the origin of the beak is the eye, consisting, as we 



