284 ARTICULATA. 



foliaceous cirri or branchiae, are furnished with two branchial tubercles which 

 occupy their superior and inferior edges. 



SPIO, Fabricins and Gmelin. 



The body slender; two very long tentacula which have the appearance of 

 antennae; eyes in the head and on each side of every segment of the body; 

 branchiae in the form of a simple filament. They are small worms from the 

 Arctic Ocean that inhabit membranous tubes. 



Si i.t.i>, Savigny. 



An odd number of tentacula articulated like the beads of a rosary, as well 

 as the superior cirri of the feet, which are simple and have but a single bundle 

 of seta 1 . It appears that there is some variety of opinion relative to the 

 existence of the jaws. 



GLYCERA, Savigny. 



The Glyceres are recognised by their head, which is a fleshy, and conical 

 point, resembling a small horn, and divided at the summit into four scarcely 

 visible tentacula. The proboscis of some still presents jaws; in others, they 

 are said to be imperceptible. 



NEPHTHYS, Cuvier. 



The proboscis of the Phyllodoces, but no tentacula; two bundles of widely 

 separated setae on each foot, between which is a cirrus. 



LUMBRINERA, de Blainville. 



The tentacula wanting; but a single small forked tubercle, from which issues 

 a little bundle of setae, on each articulation of the elongated body. If there 

 be any external organ of respiration, it can only consist of an upper lobe of 

 this tubercle. 



ARICU, Savigny. 



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, Lamarck. 



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

 long 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 proboscis 

 with neither tentacula nor jaws. 



Several species are found in the Mediterranean. 



OPHELINA, Savigny. 



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

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



