478 
THE VOYAGE OF H.M.S. CHALLENGER. 
the figure given by Malmgren the outline is unbroken. The ventral margin also 
diverges in the two forms, presenting in the new species an undulating outline, whereas 
the northern form appears to have only a uniform and slight convexity. In the other, 
and perhaps average series (PI. XXVIIIa. fig. 25), the characters are less bold, but the 
general outline, the presence of the mucro, and the shape of the anterior inferior process 
at once distinguish it from Malmgren’s representation. The hooks of the Canadian 
form closely agree with the latter series. The rows of hooks from the seventh to the 
sixteenth are double, as in the ordinary form. Four prominent papillse occur on each side 
(from the second hook-row to the fifth) between the latter and the setigerous process. 
The lobules or lamellse above the posterior hooks differ slightly from those of the 
Canadian form, the anterior being decidedly smaller, the first two especially being 
rudimentary, whereas in the latter they are large and reniform. Their condition in 
Malmgren’s form is doubtful. 
The anus is minutely papillose. 
The alimentary canal of those from Betsy Cove contained somewhat coarse sand, 
showing multitudes of fragments of silex and sponge-spicules, a few minute spines of 
Echinoderms, minute ova, fragments of Radiolarians and Diatoms. That from Royal 
Sound exhibited finer sand, sponge-spicules, and Diatoms in great abundance ; while 
•the food of those from Cape Maclear resembled the first. In the alimentary tract of 
the fragment from London River, Diatoms and sponge-spicules alone were conspicuous. 
The example from Royal Sound had beside it a large friable tube of muddy sand. 
The internal secretion is so slight that it falls to pieces on interference. Its connection 
with the specimen is open to doubt. 
The species seems to be veiy frequent in Kerguelen waters, and Kinberg mentions 
others from the neighbourhood of Rio de Janeiro. 
While the hypoderm is somewhat thinner than in the foregoing genus, the muscular 
layers are more powerful. This is especially marked in both dorsal and ventral longi- 
tudinal muscles, which form massive plates in each case. The nerve-area is bounded 
externally by a comparatively thin layer of hypoderm, and rests against the circular 
coat internally, the oblique muscles being inserted above its outer borders. 
Artacama zehuensis, n. sp. (PI. LI. fig. 7 ; PI. XXIXa. figs. 1, 2). 
Habitat . — Trawled at Station 209 (off Zebu, one of the Philippines), January 22, 
1875 ; lat. 10° 14' N., long. 123° 54' E.; depth, 95 fathoms ; bottom temperature 71°'0, 
surface temperature 81°’0 ; sea-bottom, blue mud. 
The specimen is incomplete posteriorly, but measures 70 mm. in length, with a 
diameter anteriorly of 4 -5 mm. 
