448 ANNELIDES. 



rally furnished with tentacula or filaments, to which, notwith- 

 standing their fleshy nature, some modern naturalists give the 

 name of antennae; and several genera of the second and third 

 are marked with black and shining points, usually considered 

 as eyes. The organization of their mouth varies greatly. 



ORDER I. 



TUBICOLiE(I). 



Some of the Tubicola} form a calcareous, homogeneous tube,* 

 probably the result of transudation, like the shell of the Mol- 

 lusca, with which however they have no muscular adhesion ; 

 others construct one by agglutinating grains of sand, fragments 

 of shells and particles of mud, by means of a membrane, also 

 unquestionably transuded ; the tube of others again is entirely 

 membranous or horny. To the first belongs the genus 



Serpula, Lin. 



The calcareous tubes of the Serpulae twine round and cover stones,, 

 shells, and all submarine bodies. The section of these tubes is some- 

 times round, and sometimes angular, according to the species. 



The body of the animal is composed of numerous segments^ its 

 anterior portion is spread into a disk, armed on each side with seve- 

 ral bundles of coarse hairs, and on each side of its mouth is a tuft 

 of branchiae, shaped like a fan, and usually tinged with bright 

 colours. At the base of each tuft is a fleshy filament, one of which, 

 either on the right or left, indifferently, is always elongated, and 

 dilated at its extremity into a variously formed disk which serves as 



(1) M. Savigny adds the ^renicolas to this order, and changes its name to Ser- 

 pulacea; M. Lamarck, adopting his plan, converts the Serpuiacf.a into Seden- 

 TARiA. The genera of my Tuhicolse form the family of the Amphitrites, Savigny, 

 and those of the Amphitrit.^a and Serpclacea, I.amarck. They form the order 

 EsTosiozoARiA Chetopoda Hetehochisina, Blainville, who, in defiance of his own 

 definition, places there Spio and PoLYDoaus. 



