CRABS AND SHRIMPS. 177 



seems to possess no fewer than twenty-six limbs : each 

 of which being many -jointed, and each joint, as I have 

 observed, being set with delicately-plumose hairs, the 

 whole effect is most elegantly light and feathery. 



On each side of the slender tail-like abdomen you see 

 an oval bag, connected with the body by an exceedingly 

 slender thread of communication, and tightly filled with 

 pellucid globose bodies. Like John Gilpin, of equestrian 

 fame, when 



: 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 developed only at 

 certain seasons, when the eggs, having attained 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 receptacles, being no longer needed, are 

 thrown off and speedily decay. 



Here is a second form. It is named Lynceus, and is 

 nearly as common as the Cyclops in our stagnant pools. 

 Essentially its structure is the same ; but it has this pecu- 

 liarity, that its body is inclosed within a transparent shell, 

 which is thin and flattened sidewise, and through whose 

 walls all the movements and functions of its parts are dis- 

 tinctly visible. The shell is broadly ovate in outline, 

 comes to a sharp edge all along one half of its circum- 

 ference, but is open all along the other ; as if two watch- 

 glasses were soldered together, edge to edge, and then a 

 portion of the edges ground away, so as to leave a narrow 

 but long entrance. Through this narrow orifice the limbs 

 are protruded for locomotion ; and through it the surround - 



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