32 NATURAL ARRANGEMENT OF INSECTS. 



tection, or have them so small that they can scarcely be 

 perceived. Others, again, have the peduncle entirely 

 covered with shelly granules, so that the membranaceous 

 skin can scarcely be seen; while a few, possessing the 

 compressed shelly structure of this division, are com- 

 pletely sessile. In the second great division of sessile 

 barnacles, we find modifications of form still more re- 

 markable. Some are found affixed indiscriminately to 

 marine objects, whether living or dead; others take up 

 their habitation only upon corals ; a few seem confined 

 to the backs of turtle, while the genera Tubicinella and 

 Coronula imbed themselves in the flesh on the back of 

 whales. To Dr. Leach, more than to any other natu- 

 ralist, are we indebted for the definitions of all these 

 various groups which he has proposed as genera. Mr. 

 Gray, we believe, has also illustrated their affinities; and 

 Mr. G. B. Sowerby has figured very many in his Genera 

 of Shells. On the Continent, Audouin, Wagner, and 

 Burmeister have investigated them ; and the latter in- 

 defatigable entomologist has confirmed the discoveries 

 of Dr. Thompson. 



(29.) In regard to the habits of the Cirrhipedes ge- 

 nerally, very little can be said. Destined to live in an 

 element different from that assigned to man, they are 

 seldom seen in their native haunts by the closet natu- 

 ralist. With many opportunities, in early life, for 

 studying them in a living state, we regret that other avo- 

 cations prevented this from being more than partially 

 done. There can be no doubt, however, that the Cir- 

 rhipedes are carnivorous animals, feeding upon those 

 minute polypes which swarm in all parts of the ocean, 

 although frequently invisible to the naked eye. During 

 the leisure of a voyage across the Atlantic, we had 

 once the opportunity of watching a bunch of pedun- 

 culated barnacles, taken from a piece of floating timber 

 and placed in a bucket of sea water. After a short 

 time, as if they wished to reconnoitre their new habita- 

 tion, they gradually opened the orifice in front, and pro- 



