MALENTOZOA. PEDUNCULATA. 353 



stances, while their being enveloped in a soft mantle, 

 and covered with a shell, resembling those of several 

 Mollusca, place them in connection with these animals. 

 It is alleged that in their earliest stages they are free, 

 and bear a great resemblance to certain Crustacea of the 

 lowest orders, but soon affix themselves to bodies, to 

 which they ever after adhere, and undergo a complete 

 change of form. 



They are naturally arranged under two orders : the 

 Pedunculata, and the Sessilia ; those of the former 

 section having a soft cylindrical stalk, continuous with 

 the mantle, the others being attached to objects through 

 the medium of a thin membrane or a plate of calcareous 

 matter. 



SYNOPSIS OF THE ABERDEENSHIRE SPECIES. 

 ORDER I.— MALENTOZOA PEDUNCULATA. 



The mantle prolonged beneath, and forming a fleshy 

 contractile peduncle. 



Cirripedes pedoncules, Lamarck ; Anatifes, Ferussac. 

 Pedunculus, a stalk. 



Family I. — Lepadina. 



Animal much compressed, oval or oblong, with the 

 hind part uppermost ; the branchiae numerous, pyra- 

 midal, at the base of the lower cirri ; the mantle 

 generally covered with testaceous plates of a triangular 

 form. Name from the genus Lepas. 



Genus 1. Lepas. — Animal compressed, with twelve 

 pairs of cirri ; shell subtriangular, of four lateral pieces, 

 and an elongated dorsal piece ; with a cylindrical fleshy 

 peduncle. Aenas, a limpet, or barnacle-shell. Linnseus. 



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