CLASS OF CRUSTACEA. 491 



we must arrange the cirrhipeda, which at first sight seem to 

 have many analogies with the mollusca, more so indeed than 

 with animals of the class we now describe ; but in fact they 

 are only Crustacea with the hody deformed after they have 

 ceased to lead a wandering life. When young, these small 

 beings, which are all marine, swim freely, and resemble 

 extremely certain ordinary entomostraca, such as the young 

 cyclops (Fig. 158) ; but soon afterwards they become fixed, 

 so long as their life endures, to some submarine body, and 



Fig. 521. Anatifae; Barnacles. 



completely change their form. It is by the back that they 

 thus adhere, and their body, more or less pyriform and 

 curved on itself, is enclosed, in whole or in the greater part, 

 in a kind of shell, composed of several pieces (Fig. 521). 

 They have no eyes, and their mouth is furnished with man- 

 dibles and jaws having the strongest resemblance with those 

 of certain Crustacea ; the abdominal aspect of their body is 

 occupied by two rows of fleshy lobes, having each long horny 



