70 MEMOIR IV. 



The animals embraced under the title of Cirripedes by 

 Naturalists, are familiarly known in these countries by the 

 name of Barnacles. Two very different types are included 

 under this comprehensive name, viz. the families of Lepas 

 or true Barnacles, (shewn in the wood cut) and that of 



the Balani or the acorn-shells of British Conchologists 

 (PI. IX. f. 11, 12.); the former elevated on a membraneous 

 pedicle, the latter sessile and provided with a domicile 

 wholly calcareous ; both are marine, and several species 

 of either, amongst the most abundant and common produc- 

 tions, the Balani attaching themselves for the most part 

 to the surface of rocks, stones and other ^^erf bodies, and 

 are consequently littoral, the Lepades on the contrary are 

 rarely found o\^ fixed bodies, but almost always on such as 

 float upon the surface of the open ocean, as Fuci, pieces of 

 wood, and the bottoms of ships, by which means they 

 participate in the benefits of the vagrant life of those 

 Crustacea which are gifted with perpetual freedom of 

 motion. In this distribution of the Cirripedes throughout 

 the ocean, we recognize the operations of Superior Intel- 

 ligence, as well as in the peculiar structure of these curious 

 and interesting animals, which fits them so admirably to 



