DORSIBRANCHIATA. 299 



Ahicia, Sav. 

 The teeth and tentacula wanting; two ranges of lamellated cirri on the 

 back of the elongated body; anterior feet furnished with notched crests not 

 found on the others. 



Hesione, Lam. 



A short thick body composed of but few and feebly marked rings; a very 

 lo'ig cirrus, that probably exercises the functions of branchiae, on the top 

 of each foot, which has another beneath with a bundle of setae; a large pro- 

 boscis with neither tentacula nor jaws. 



Several species are found in the Mediterranean. 



Ophelina, Sav. 



The body thick and short, with feebly marked rings and scarcely visible 

 setae; long cirri in lieu of branchiae on two thirds of its length; palate of the 

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

 the two superior are the largest. 



CiRRHATULus, Lam. 



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, Sav. 

 The Palmyrx are recognized by their superior fasciculi, the setae of which 

 are large, flattened, flabeUiform, 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 c>ne to two 

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



Aphrodita, Lin. 

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

 branous scales that cover the back, to which, through a very groundless 

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

 chiae, 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 cESophagus is susceptible 

 of being protruded like a proboscis. M. Savigny distinguishes 



Haiithea, Sav. 

 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 co- 



