THEIR YOUNG. 



301 



V 



active animals they resemble in many points. This 

 affords another link by which the Cirrhipoda are con- 

 nected with Crustacea. The young Cirrhipode bears 

 little or no resem- 

 blance to its ma- 

 ture condition. It 

 is about the tenth 

 of an inch long, 

 lodged in a pair 

 of shelly valves, 

 united like those 

 of a bivalve shell, 

 and large enough 

 to admit of the 

 whole animal be- 

 ing withdrawn in- 

 to them. This shell 

 opens in front, to 

 allow the animal to 

 extend its legs and 

 arms. It has two 

 long arms, furnish- 

 ed with a sucker 

 and hooks, and six pairs of legs, formed for swimming. 

 These are so arranged as to act in concert, and by their 

 simultaneous stroke on the water to drive the little 

 body forward in a succession of bounds. It has also a 

 tail tipped with four bristles, and commonly folded up 

 under the body; and it has a pair of large pedunculated 

 eyes. The whole animal is so like one of the humbler 

 Crustaceans, that it might well pass for one of them. 



