248 AMPHITRITE. 



1. FABRICIA. Plate XXXI. Figs. 10, 11. 



A minute animal, dwelling on shores, bears so much resemblance to 

 one denominated Fabricia by Muller, in honour of a distinguished natu- 

 ralist, that I shall not venture to assign it any other name. Fabricius, 

 indeed, ascribes twelve segments to the body of his specimen, and Dr 

 Johnston thirteen. Mine have had only six, whence, from that and 

 other things, I cannot positively identify it with theirs ; and, before being 

 aware of its having been observed by them, I had proposed to call it the 

 Amphitrite palmata. 



This animal consists of a body composed of about six segments, 

 crowned by a plume. Its total length about a line, and the expansion 

 of the plume is as much. The latter consists of six compartments, each 

 being a rib bordered by long tentacula, and each tentaculum fringed by 

 cilia. Two black specks are on the neck. A bristle is on each side of 

 the segments of the body. 



This animal dwells in a tube of its own fabrication, four lines long, 

 and narrow. When the water is rendered turbid, the plume or branchiae 

 may be observed protruding as a pencil from the tube, and particles are 

 transmitted down the centre of the ribs, as the animal revolves like the 

 Amphitrite. I have been unable, however, to discover tentacula within 

 the plume, or trowels without it. 



Fabricius says that it cannot resume its place in the tube after 

 having been dislodged. 



Specimens have survived four or five months in confinement, during 

 which time the tube received sensible accessions. 



This animal dwells in pools near low water. As it is said that a 

 later naturalist has named a different product Fabricia, Dr Johnston 

 proposes that it shall be now denominated Othonia, thus still retaining 

 the Christian name of Fabricius. 



PLATE XXXIf? 



FIG. 10. Fabricia. 



1 1 . Another specimen. 



