352 
THE VOYAGE OF H.M.S. CHALLENGER. 
Family Ariciida:. 
The Ariciidse would not appear to be frequent in the expeditions hitherto recorded. 
Thus none occur in Grube’s Annulata ffirstediana, none in his description of those from 
the “ Gazelle,” and only a single Aricia is described by Schmarda. Though some occur 
at very great depths, as, for instance, Aricia norvegica, still others frequent the shore 
between tide-marks, and therefore might have been the more easily procured. It is 
not a group, however, that would readily be noticed, unless specially looked for. Sand, 
often very coarse sand, forms the chief contents of the alimentary canal. 
Aricia, Savigny. 
Aricia norvegica, Sars. 
Habitat. — Dredged at Station 47 (off the coast of New York), May 7, 1873 ; 
lat. 41° 14' N., long. G5° 45' W.; depth, 1340 fathoms; surface temperature, 42°’0 ; sea- 
bottom, blue mud. 
A fragment of the anterior end, measuring about 12 mm. in length and 2 ’5 mm. in 
iDreadth. 
The snout and anterior region agree with these parts in Aricia norvegica, Sars, of 
which it seems to be a variety. The first four bristled segments are devoid of branchiae, 
which commence on the fifth. 
A variety of the same form was procured in the trawl off Kio San Francisco, 
September 12, 1873, in 1200 fathoms; lat. 10° 46' S., long. 36° 2' W. ; sea-bottom, 
mud. 
This consisted of a fragment of the anterior region, 18 mm. in length and 3 mm. in 
diameter. While agreeing in most respects with Aricia norvegica, it is observed that the 
double external process of the foot has a longer pedicle, and the tips of the large spear- 
shaped brownish bristles of the posterior serrated segments (13-15) are, in some cases, 
slightly bent. A tendency to the latter, however, is sometimes noticed in Norwegian 
examples of Aricia norvegica. 
In the section of this form the cuticle is comparatively thin, but the hypoderm is 
moderately developed, especially on the dorsal and lateral regions. The circular coat is 
well-marked interiorly, but it is broken up laterally at the feet ; while dorsally strong 
Inands pass from it vertically through the dorsal longitudinal muscles, which are thus cut 
into separate fasciculi. The dorsal muscles are much less than the ventral longitudinal, 
and their shape is somewhat ovoid. The ventral muscles again are elongate in transverse 
section, and are firmly Ijound by the circular coat externally and the oblique muscles 
internally. Vertical filjres also separate them into narrow fasciculi. The powerful oblique 
