Gatty Marine Laboratory, St. Andrews. 61 



the branchial basal region or pedicle more prominent and 

 the tentacles on each side of the fissure well developed. 

 ]\Ioreover, the collar is narrower^ and it slopes from below 

 upward and backward to the dorsal surface, where it ends 

 in a broad, free, V-shaped pocket on each side — separated 

 by a central fissure. Instead of the high fold on each 

 side of the dorsal fissure the narrow collar makes a W of a 

 characteristic form, since the inner margins run forward 

 to the median groove of the pedicle, and the whole 

 facies of the anterior end differs. A glandular or 

 tubular organ is visible in each space of the W, for the 

 cephalic plate is largely exposed in a dorsal view ; ventrally 

 the mouth appears as a longitudinal slit with thickened 

 edges below the basal pillars of the branchiae, and in some 

 the thin buccal membrane is distended with rand. More- 

 over, the ventral margin of the collar is symmetrically 

 sinuous, being prominent at the sides, and then passing with 

 a curve to the central dimple. A distinctive feature is the 

 prominence of the bases of the branchise, and their separation 

 anteriorly. 



The body, which is about 2 inches long and \ inch in 

 diameter, is somewhat flattened anteriorly, more rounded 

 posteriorly, and the segments appear to range from sixty to 

 seventy. From the mid-dorsal fissure a groove passes 

 backward to the posterior border of the eighth bristled 

 segment, runs in the furrow between the eighth and ninth, 

 then ventrally crosses the ninth obliquely to the middle 

 line, and then passes to the posterior end. The segments 

 are distinctly marked, those of the anterior region presenting 

 a two-ringed condition ventrally. It tapers gently poste- 

 riorly, and then rather abruptly ends in a point with the 

 anus at the tip, the segments being numerous and crowded 

 in this region. 



The branchiae are of considerable length, are devoid of 

 a web, and have a regularly camerated axis continued as a 

 slender central process in the very long, tapering, terminal 

 process, which has a few short pinnae or papillae at its base, 

 the longer pinnae gradually diminishing and ceasing at the 

 base of the process. The number of the branchiae would 

 appear to be about a dozen on each side, and, besides the 

 filiform cirri, two short, flattened, tapering tentacles occur 

 dorsally. 



The anterior segments have a median prominence in the 

 form of a flattened cone laterally, and thus the bristles are 

 unusually conspicuous, especially as a distinct setigerous 

 process is present. The first tuft is composed only of 



