TUBICOLA. 295 



the tube of others again is entirely membranous or horny. To the 

 first belongs the genus 



Serpvla, Lin. 



The calcareous tubes of the Serpulse twine round and cover stones, shells, 

 and all submarine bodies. The section of these tubes is sometimes round, 

 and sometimes angiilar, 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 several bundles of 

 coarse hairs, and on each side of its mouth is a tuft of branchije, 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 an operculum, and seals up the orifice of the tube when the 

 animal has withdrawn into it. 



Serp. contortuplicata. The most common species; its tubes are round, 

 three lines in diameter, and twisted. The operculum is infundibuliform, 

 and the branchise ai*e frequently of a beautiful red colour, or variegated 

 with yellow, violet, &c. Vases or other objects thrown into the sea are soon 

 covered by its tubes. 



Sabella, Cuv. 

 The same kind of body, and similar flabelliform branchiae, as the Serpulse; 

 but the two fleshy filaments adhering to these branchiae both terminate in 

 a point, and without forming an operculum; sometimes they are even want- 

 ing. The tube of the Sabellae is most commonly composed of granules of 

 clay or mud, and is rarely calcareous. 



The species known are large, and their fan-like branchiae remarkable for 

 their delicacy and brilliancy. 



Sah. protula, Cuv. A large and splendid species inhabiting the Mediter- 

 ranean. Its tube is calcareous like that of the Serpulae, its branchiae orange 

 coloured, &c. 



Terebella, Cuv. 

 The Terebelke, like most of the Sabellae, inhabit an artificial tube, but it is 

 composed of grains of sand and fragments of shells; their body, moreover, has 

 fewer rings, and their head is otherwise decorated. Numerous filiform and 

 extremely extensible tentacula surround their mouth; their branchise, placed 

 on the neck, are not infundibuliform, but resemble arbusculae. 



Amphitrite, Cuv. 

 The Amphitrites are easily recognized by the golden coloured setae, arranged 

 like a crown, or the teeth of a comb, in one or two rows, on the anterior 

 part of their head, where they probably serve as a means of defence, or 

 perhaps enable the animal to crawl, or to collect the materials of its tube. 



