CIRRHIPEDES. 595 



The cloak consists of three membranes. The external 

 one is the cuticle, and invests the whole external surface of 

 the animal. Underneath this is the true skin, in which are 

 formed the testaceous plates that protect the body. These 

 plates or valves are evidently formed in the same manner 

 as common shell, the layers of growth being indicated by 

 the strias on the surface. The inner membrane forms a 

 sac for the body itself. This bag is closed on all sides, ex- 

 cept opposite to the abdomen^ where there is a slit, through 

 which the feet are protruded. 



The peduncle consists of the two external nIembraneS of 

 the integuments of the body. The cuticle covers its sur- 

 face, and even the base by which it adheres. The true 

 skin is covered on its central aspect with numerous n^uscu^ 

 lar threads. The summit of the peduncle next the head is 

 covered with the inner membrane of the cloak, through 

 which, however, there is a perforation, corresponding to a 

 large vessel which descends along one of the sides of its cen- 

 tral cavity. This cavity, in the Lvpa's anatvfera^ Cuvier 

 found filled with a white cellular substance soaked with 

 mucus. Ellis, on the other hand, found the peduncle 

 of what has usually been regarded as the L. aurita of 

 Lin., " full of a soft, spongy, yellow substance, which ap» 

 peared, when magnified, to consist of regular oval figuresj 

 connected together by many small fibres, and no doubt are 

 the spawn of this animal." This view of the subject enter- 

 tained by Ellis, may, upon investigation, lead to the con- 

 clusion, that the cavity of the peduncle^ and its lateral ves- 

 sel, are connected with the reproductive organs. It would 

 be desirable to have the branched peduncles dissected with 

 care, as a knowledge of their structure might throw some 

 light on the mode of growth of these animals. 



Family 1. — Tunic protected by five testaceous plates ; 

 the peduncle naked. This includes the following genera J 



VOL. n. 



PP 



