32 THE ANNELIDA POLYCHAETA. 



EUPHROSYNIDAE. 



These are forms of small or medium size in which the body is oblong or 

 elliptic, with the dorsum in some degree arched and the venter flattened. The 

 number of somites is comparatively small, being mostly between twenty and 

 sixty. 



The prostomium is small and compressed and bends down anteriorly to the 

 ventral surface. It bears typically four eyes, two dorsal and two ventral, and 

 three tentacles, a median and two lateral ones arising ventrally, or rarely no 

 tentacles present (Lophonta). Palpi adnate at border of mouth. A caruncle 

 present, distinct. 



Mouth ventral, extending over several somites. 



Parapodia with rami fused and extending as a transverse ridge upon the 

 dorsum toward the median line, the ridge bearing setae and branchiae. A 

 ventral cnrus and from one to three dorsal cirri present. The branchiae on 

 the dorsal extension of the parapodia are arranged in transverse series, in such 

 manner that with the accompanying setae they leave free only a narrow median 

 longitudinal band. The branchiae are branched, pennatifid, or arborescent. 



Setae simple, the ventral ones commonly unequally and conspicuously 

 bifurcate distally. Dorsal setae rarely replaced by stout paleae. 



Pygidium with two processes or an undivided rim. 



The euphrosynids may occur at considerable depths, but are most frequent 

 in the Uttoral region as with the amphinomids. 



The genus Lophonta of Costa is insufficiently known. It is placed with 

 Euphrosyne tentatively because of the arrangement of the gills in transverse 

 series. 



Key to Genera. 



a. Tentacles absent Lophonta Costa. 



aa. Tentacles present. 



h. Only one dorsal cirrus; dorsal setae in the form of large flat paleae. . . . Palmyrcuphrosyne Fauvel. 

 bb. Two (or three) dorsal cirri present; dorsal setae not thus modiSicd. .. .Euphrosyne Savigny. 



Euphrosyne Savigny. 



Descript. Egypte. Hist, nat., 1809 (= 1822], 1, pt. 3, p. 63; Audouin & Milne Edwaed.s, Hist. nat. 

 litt. France. Annclides, 183-1, 2, p. 124; Ehlers, Borstenwiirmcr, 1861, p. 61; Gkube, Annulata 

 Semperiana, 1878, p. 11; McIntosh, British annelids, 13D0, 1, pt. 2, p. 233. 



Euphrosine Cuvier, Regne anim. ed. 2, 1829, 3, p. 199; Blainville, Diet. sci. nat., 1828, 57, p. 199. 



