EURYTHOE BOBEALIS. 225 



The head is pale, somewhat horse-shoe shaped, with two short, conical, awl-shaped 

 tentacles in front, and two longer ones — stylodes (Racovitza) — a little behind, opposite the 

 wide part of the snout. A curved line separates the anterior from the posterior part of 

 the head (Plate XXVII, fig. 16), the former being flattened, the latter more elevated, and 

 furnished with four reddish eyes, the anterior being about twice the size of the posterior 

 pair. A little behind the anterior pair a filiform tentacle projects upward in the middle 

 line, and, immediately behind, the caruncle extends as a wrinkled ridge to the anterior 

 border of the third bristled segment, and is of the yellowish colour of the rest of the 

 dorsum. 



The body is elongated, nearly cylindrical throughout the greater part of its length, 

 only a little tapered at the extremities. The number of segments is sixty-seven in the 

 larger, forty-one in the smaller specimens. In contraction the body is somewhat square 

 in transverse section, the inferior surface especially beiDg flattened. The great shorten- 

 ing which takes place causes the prominent rows of bristles to project very boldly. The 

 sulci between the first three bristled segments are somewhat less marked, and the slope 

 of the bristles more oblique, but the rest are very distinctly separated, indeed the body is 

 occasionally more or less moniliform. The first bristled segment is small and has no 

 branchiae. The second has a tuft of about four papilliform branchial processes. Each 

 segment is furnished with a dorsal and ventral division of the foot — bearing bristles, 

 besides the branchial tuft which springs from a point behind and rather below the dorsal 

 fascicle of bristles, and consists of about four finger-like processes arising from a common 

 origin. They continue almost to the tip of the tail, being apparent on the third last 

 segment. All are pale in colour. 



The dorsal division of the foot (Plate XXXVI, fig. 16) has a jointed cirrus, and a 

 group of bristles consisting — of bifid forms with elongate finely serrate tips (Plate 

 XXXV, figs. 20 and 21), of those with shorter tips with four or five serratures, and of 

 somewhat stronger tapering simple bristles with serrate tips (Plate XXXV, fig. 22). 



The inferior division has also a jointed cirrus, and many bifid bristles somewhat 

 stouter than in the superior division, and with shorter tips having about four serratures 

 (Plate XXXV, fig. 23). 



The tail terminates in a rounded papilla with a minutely crenate margin. 

 The proboscis commences at the posterior third of the fourth bristled segment (as 

 indicated by two brownish specks), and occupies the fifth and sixth segments. It is 

 somewhat fusiform, truncated anteriorly and posteriorly. 



The specimens were of a general straw-yellow hue, somewhat paler anteriorly, and 

 pinkish here and there from the dorsal blood-vessel. 



The animal is sluggish, crawling slowly about, and contracting: into a bristled 

 mass when irritated. Occasionally the posterior extremity is twisted like a screw, and 

 it also coils its body into one or two convolutions, the condition it assumes in spirit; 

 hence the examination is rendered difficult, and most of the fragile bristles are broken 

 during the efforts to decipher their structure. 



This form seems to be the same as that found by Prof. M. Sars in 1861, though the 

 brevity of his description leaves some doubt. His sole specimen was a small one of 10 

 mm. in length, and occurred at a depth of sixty to seventy fathoms. As in other types 



