430 
THE VOYAGE OF H.M.S. CHALLENGEE. 
The length of the injured fragment, which consists of the anterior region, is about 
34 mm., and its diameter at the base of the paleolse 3 ‘5 mm. The species is therefore of 
considerable size, since the bristled region only is present. 
The snout agrees in general characters with the ordinary forms, the oblique (ocular '?) 
ridges being very prominent. The broad double eminence between the branchiae is well 
marked. There are seventeen pairs of bristle-bundles. The first or paleolae are long 
tapering organs, with a slight curve toward the tip, which has a trace of a wing on each 
side, as in allied species. This condition doubtless indicates the morphology, viz., that 
each group consists of one of the lateral bristle-tufts modified and directed forward. 
The lateral bristles behind the foregoing present a narrow wing on each side, and their 
extremities are long, finely tapered and curved. The wing is just perceptible on the 
slender intermediate forms. 
The hooks (PL XXVIIa. fig. 1) have four or five large teeth, with a process beneath 
the lower one, and the curves of the terminal or anterior inferior process are character- 
istic. Five seems to be the most common number of teeth. In shape these hooks come 
nearest to the Canadian form of Amphicteis gunneri, and it is remarkable to notice how 
closely all these forms approach each other. 
The specimen occupied a massive tube of dark greyish mud, lined internally by 
chitinous secretion. The diameter of the tube is 11 mm., and the length of the longest 
piece 80 mm., but part of this is less bulky than the foregoing. Here and there amongst 
the mud of the tube externally the same rounded ochreous arenaceous Foraminifera 
occur as in Myriochele lieeri} The mud, moreover, shows numerous sponge-spicules and 
a few Diatoms. The grains of sand forming the tests of the arenaceous Foraminifera are 
very minute. 
The hypoderm of Amjjhicteis sard is moderately developed, except over the nerve- 
area, where it is thicker. The nerve-cords are placed somewhat deeply with regard to 
the surface, for the circular coat bends inward so as to cause them to bulge into the 
perivisceral chamber. The size of the longitudinal ventral muscles is considerable. 
Amj)hicteis wyvillei, n. sp. (PI. XXVIIa. fig. 2). 
Habitat. — Trawled at Station 147 (midway between Prince Edward and Kerguelen 
Islands), December 30, 1873; lat. 46° 16' S., long. 48° 27' E.; depth, 1600 fathoms; 
bottom temperature 34°'2, surface temperature 41°'0 ; sea-bottom. Diatom ooze. 
A form of considerable size, though not quite complete posteriorly, measuring 39 mm. 
in leno-th and 3 mm. in diameter exclusive of the feet. The vicissitudes connected with 
its removal from so great a depth have injured the sj^ecimen. 
The head agrees in general eharacters with that of Amphicteis gunneri, and the first 
^ Vide page 412. 
