DORSIBRANCHIATA. 395 



gills are in the form of very broad leaves, forming a range on each side of the body, upon which minute 

 vessels ramify extensively. '* 



The iV. viridis, MuUer, of which M. Savigny, without having seen it, proposes to make a genus Eutalia, and the 

 two species of Eunomia, Risso, appear to me to belong to Phyllodoce, to which also, perhaps, should be referred the 

 Nereis pinnigera, Montagu, and the N. stilUfera, Muller, which M. Savigny, without seen them, proposes to make 

 into a genus Lepidia, and N. longa, Otto, which M. Savigny places with N.flava in his genus Etiona. All these 

 require to be examined anew after the method detailed by M. Savigny. The genus Phyllodoce, Sav., however, must 

 not be confounded with that of M. Ranzani, which latter is allied to Aphrodita, and especially to Polynoe. 



Alciope, Aud. & M. Edwards, — 

 Have nearly the mouth and tentacles of Phyllodoce, but the feet present, besides the tubercle which 

 bears the bristles and the two foliated cirrhi, or gills, a couple of branchial tubercles, which occupy its 

 upper and lower borders. 



Spio, Fabricius & Gmelin. 

 A slender body ; two very long tentacles that have the appearance of antennae ; eyes upon the head, 

 and on either side of each segment of the body a gill in form of a simple filament. They are small 

 northern Sea-worms, which inhabit membranous tubes, 

 Polydore, Bosc, appears to me to be referrible to this genus. 



Syllis, Sav. — 

 Have tentacles of uneven numbers, articulated in chaplets, together with upper cirrhi to the feet, 

 which are very simple, and bear no bundles of silky bristles. It appears that they vary with respect 

 to the existence of jaws. 



S. monilaris, Sav. [figured in p. 391 ante], the Nereis annularis, Muller, of which M. Savigny, without having 

 seen it, proposes to make a genus, which he terms Lycastis, having tentacles and cirrhi in chaplets, like a Syllis; 

 but the former, represented to be of even number, requires farther examination. 



Glyceris, Cuv. — 

 Are recognized by the form of the head, which terminates in a conical fleshy point, having the aspect 

 of a small horn, and the summit of which divides into four very small tentacles, that are scarcely visi- 

 ble. The trunk of some of the species contains jaws, which cannot be perceived in others. 

 Such are Nereis alba, Muller, and Glye. Meckelii, Aud. & Edw. 



Nephthys, Cuv. 

 The trunk of Phyllodoce, but no tentacles ; and on each foot two bundles of bristles widely sepa- 

 rated, and a cirrhus between them. 



LoMBRiNEREis, Blainv. — 

 Have no tentacles ; the body, considerably elongated, has merely a small forked tubercle at each arti- 

 culation, which bears a little packet of silky bristles. If there be any external respiratory organ, it 

 can only be the upper lobe of this tubercle. 



Nereis abranchiata, Poll., Lio?i6ric!w/rairj7i*, Muller, of which latter M. Blainville makes, but doubtfully, his 

 genus tScoletome. 



The Scolelcpe, Blainv., which are only known by the figure of Abildgaart {Liimbricus squamatus), have a very 

 slender body, with numerous rings, each of which has a cirrhus that serves for a gill, and two bundles of silky 

 bristles, the lower of which seems to consist of a fold of skin compressed like a scale, and the head has neither 

 jaws nor tentacles. 



Aricia., Sav., — 

 Have neither teeth nor tentacles. The body, which is lengthened, bears two ranges of lamelliform 

 cirrhi along the back ; and the anterior feet are furnished with dentelated crests, that do not occur on 

 the other feet. 



Ar. Cuvieri, Aud. and Edw. The Lumbricus armiger, Muller, which M. Blainville, without having seen it, pro- 

 poses to make a genus of, by the name of Scolople, appears to have neither teeth nor tentacles, and bears two 

 small simple bundles of short bristles on its first segments, and on the rest a bifid tubercle, a little bristle, and a 

 long and pointed branchial lamina. 



Hesione, — 

 Have a short and rather thick body, composed of few ill-defined rings : a very long cirrhus, which pro- 

 bably fulfils the ofiice of branchias, occupying the upper part of each foot, which has also another 

 lower one, and a packet of silky bristles, and the trunk large, having neither jaws nor tentacles. 

 Such are //. splendida, Savigny, H.festina, Id., and II. pantherima, Risso. 



