224 EURYTHOE BOREALIS 



Genus II. — Eukythoe, Kinberg, 1857. 



Body elongated, with flattened rectangular segments. Cephalic lobe large, rounded 

 or pentagonal ; eyes four, dorsal; a median, and two lateral tentacles ; caruncle trilobed. 

 Palpi forming two adnate lobes interiorly in front of the mouth, each with a tentacular 

 process or sty lode (Eacovitza). 



Dorsal cirrus single ; bristles of the dorsal lobe linear, subarticulate, others subbifid, 

 with a serrate limb and a short process. Ventral bristles bifid. Branchige from the third 

 segment backward. 



Eurythoe borealis, Sars, 1861. Plate XXVII, fig. 16. 



Specific Characters. — Head somewhat horse-shoe shaped, with two short awl-shaped 

 tentacles (lateral) in front, and two longer a little behind. A curved line separates the 

 head into an anterior and a posterior region, the latter more elevated and furnished with 

 four reddish eyes, the anterior being about twice the size of the posterior. A little 

 behind the anterior pair is a filiform tentacle, while behind the eyes the caruncle 

 extends to the anterior border of the third bristled segment. Body elongate, straw - 

 yellow or pale vermilion, twenty-three to sixty- seven segments, and in transverse 

 section nearly square, though the ventral surface is most flattened. Branchiae commence 

 on the second bristled segment as a tuft of four papilliform processes, and generally arise 

 , behind and somewhat below the dorsal fascicle of bristles, and consist of a tuft of three 



or four pale finger-like processes. They are continued almost to the tip of the tail 

 (antepenultimate segment), which terminates in a rounded papilla with a minutely 

 crenate margin. The dorsal division of the foot has a jointed cirrus, and bristles of two 

 kinds — bifid with a serrated limb of greater or less length, and somewhat stronger simple 

 bristles with serrate tips. The ventral division has also a jointed cirrus, and many bifid 

 bristles somewhat stouter and with shorter tips (about four serratures). Length one to 

 one and a half inches. 



>-f *- ♦; 



\k Synonyms. 



1861. Eurythoe borealis, Sars. Vid. Selsk. Forh., 1861, p. 56 (p. 9 sep. copy). 

 1869. Amphinome vagans? Mcintosh. Trans. R. S. E., vol. xxv, p. 406, pi. xv, £. 1. 

 1876. Eurythoe borealis, Mcintosh. Trans. Z. S., vol. ix, p. 373. 

 18&6. ,, „ Eacovitza. Arch. Zool. Exp., 3e ser., iv, p. 179, pi. i, f. 1 — 6. 



Mabitat.—JJnder a stone in a tide-pool in Herm, August, 1868. Sars found a 

 smaller example at Manger, in the neighbourhood of Bergen, in shell-sand. 1 



1 It is doubtful if Dr. Benham's view that specimens six inches long occur all round the British 

 area refers ta this species, which appears to be rare in our seas. 



