CIRRHOPOD. 



81 



more closely allied to 

 articulated animals. 

 In the early period 

 of their existence all 

 these creatures are 

 marine, and swim 

 readily, and resem- 

 ble, particularly in 

 their organization, 

 certain inferior crus- 

 ta'ceans ; but very 

 soon after birth, they 

 permanently attach 

 themselves to some 

 submarine body, and 

 entirely change their 

 form. In this man- 

 ner they are fixed by 

 the base. The body- 

 is more or less pyri- 

 form and doubled on 

 itself, and is enclosed 

 entirely, or in part, 

 in a kind of shell 

 composed of several 

 pieces. They have 

 no eyes, and the 



Fig. 70. CIKRHOPOD or CIRRIPED. 



mouth is furnished 

 with mandibles and 



jaws, closely resembling those of certain crusta'ceans ; the ab- 

 dominal face of the body is occupied by two rows of fleshy 

 lobes, each one bearing two long horny appendages (c), armed 

 with cilise, and composed of a multitude of little articulations, 

 corresponding in a manner to the fins or feet found under the tail 

 of several crusta'ceans. These arms or cirri, of which there are 

 twelve pairs, are doubled on themselves, and the animal is con- 

 stantly drawing them in and then protruding them through the 

 opening of its sheath. The nervous system consists of a double 

 series of ganglia, arranged like that of other articulated animals. 



Explanation of Fig. 70. A Pentalasmis or anatifa, represented with one- 

 half the shelly covering removed to show the body : a, a, shell ; 6, 6, the 

 body, which is soft, enclosing the principal viscera ; -, the mouth, seen 

 from the ventral aspect, the oral aperture appears to be raised on a promi- 

 nent tubercle ; J, </, J, fleshy appendages which constitute the respiratory 

 or branchial organs ; c, c, flexible arms, or cirri ; /, muscle for protiuding- 

 the cirri through the slit of the mantle ; /, the pedicle or base by which 

 the animal attaches itself to submarine bodies. 



