320 ON THE CLASSES OF THE 



together. These smaller links of the great chain appear 

 to have no very distinct type of peculiar construction. 

 They are all very imperfect beings, and seem in general 

 to be compounded of properties which more peculiarly 

 belong to the two great divisions which they link together ; 

 or, if their structure may be referred to any one type, it is 

 undoubtedly to that of the circle of Acrita. When a 

 Cuttlefish has been confounded by Gmelin with the Po- 

 lypes, when the intestinal Acrita are not even to this day 

 clearly distinguished from Worms, when Savigny and Le 

 Sueur have only just separated the Tunicata from other 

 Compound animals, and Lamarck still places Zoanthus 

 with Hydra; it seems extraordinary that the gregarious 

 disposition of the Cirripedes, their testaceous covering 

 and long arms should not have given them also a place 

 among the Acrita. They certainly deserve it better than the 

 Cephalopoda, with which they were confounded by no less 

 a naturalist than Poli. But however this may be, it is 

 clear that the type of an osculant group, such as the Tu- 

 nicata, Cephalopoda, Annelides, Cirripeda, and Zoan- 

 thida, will find its corresponding form rather among the 

 circle of Acrita than among any other of the great divi- 

 sions, unless it be at the points of connexion. A curious 

 exception however to the full force of this remark seems 

 necessary to be made with respect to the Annelides; for 

 we have only to cast a glance at the systems in present 

 use, in order to be convinced that the external form and 

 manners of some of these animals announce a certain de- 

 gree of kindred or analogy with both the Mollusca and 

 Radiata. But it is possible that what has been already 

 said on the affinity which opposite points of a circle bear 

 to each other, will serve to explain this circumstance. 



