DORSIBRANCHIATA. 285 



mouth with a dentated crest ; the lips surrounded with tentacula, of which 

 the two superior are the largest. 



CIRRHATULUS, Lamarck. 



The branchiae consisting of a very long filament ; two small bundles of setae 

 to each of the articulations of the body, which are numerous and compact ; 

 a series of long filaments round the nape. The slightly marked head has 

 neither tentacula nor jaws. 



PALMYRA, Savigny. 



The Palmyras are recognised by their superior fasciculi, the setae of which 

 are large, flattened, flabelliform, and glisten like highly-polished gold ; their 

 inferior fasciculi are small; their cirri and branchiae feebly marked. They 

 have an elongated body, two extended tentacula, and three very small ones. 



Palm, aurifera, Sav. The only species known ; it is from one to two inches 

 in length, and is found at the Isle of France. 



APHRODITA, Linnceus. 



This genus is easily known by the two longitudinal ranges of broad 

 membranous scales that cover the back, to which, through a very ground- 

 less assimilation, the name of elytra has been given, and under which their 

 branchiae, in the form of fleshy crests, are concealed. 



Their body is usually flattened, and shorter and broader than in the other 

 Annulata. Their extremely thick and muscular oesophagus is susceptible of 

 being protruded like a proboscis. M. Savigny distinguishes 



HALITHEA, Savigny, 



Where there are three tentacula, a small crest between two of them, and 

 where the jaws are wanting. 



A species is found on the coast of France, which, with respect to its colour- 

 ing, is one of the most splendid of all animals the Aphrodita aculeata, Lin. 

 It is oval, from six to eight inches in length, and from two to three in 

 breadth. The scales on its back are covered and concealed by a sort of stuff 

 resembling tow, which arises from the sides. From the latter also spring 

 groups of stout spines, which partly transfix the tow, and fasciculi of flexuous 

 setae of a splendid golden colour, whose changeable tints rival those of the 

 rainbow. They are not inferior in beauty to the plumage of the Humming- 

 bird, or to the lustre of the richest gems. Farther down is a tubercle from 

 which arise three groups of spines, of as many different diameters, and finally, 

 a fleshy cone. There are forty of these tubercles on each side, and between 

 the two first are two small fleshy tentacula. There are fifteen pairs of wide, 

 and sometimes inflated, scales on the back, and fifteen small branchial crests on 

 each side. 



