REPORT ON THE ANNELIDA. 
479 
In the general form of the body it agrees with the preceding species. The cephalic 
tentacles, however, are much more delicate and filiform. The branchiae likewise are 
somewhat finer and more numerous, forming three dense wavy masses on each side. 
The proboscis has much more minute and more numerous papillae ; and the furrows on 
the buccal segment are more regular and symmetrical. 
The bristles (PI. XXIXa. fig. 1) are somewhat longer than in the preceding species, 
and the tips are much more attenuate and tapering. The wings, moreover, are narrower, 
and show very distinctly the oblique striae, frequent in such forms. The shafts are 
straight, but the tips are slightly bent. The tufts are decidedly larger than in the 
former species, both as regards the setigerous processes and the number . of the 
bristles. 
The hooks (PI. XXIXa. fig. 2) differ from those of the preceding form (Artacama 
challengerice) in the more pronounced prominence of the heel, in the deeper inflection 
beneath it, and in the smaller incurvation just below the anterior inferior projection. 
The distance between the base of the great fang and the point of the mucro is greater 
in the present than in the former species, and the incurvation below it is also deeper. 
The crown is somewhat less elevated and more pointed than in Artacama challengerice, 
the base of the hook is longer, and quite different in character from that in the species 
referred to. 
Another evident distinction between this form and Artacama challengerice is the 
diminution of the lamellae on the posterior setigerous processes. They are hardly 
noticeable in the first four or five, and at no part of the animal do they surpass in size 
the setigerous process. When fully developed they form somewhat ovoid structures 
attached to the upper end of the setigerous lamellae. Some in front are pointed 
distally, but their softened state renders the description somewhat unsafe. 
The intestine contains a large amount of dark greyish mud, in which sponge- 
spicules, spines of an Annelid, Foraminifera of various kinds, minute spiral shells of 
Pteropods, Diatoms, and hairs of minute Crustacea occur amongst the sand-grains and 
debris. 
The size of the muscles exceeds that in Artacama challengericB. The longitudinal 
dorsal being nearly twice the bulk of the ventral in section. The long median fissure 
between them is occupied by the suspensory fibres of the alimentary canal. The oblique 
muscles are conspicuously powerful, and a depression occurs at each raphe in con- 
traction. The nerve-area is similar to that in the former species, though somewhat 
less. 
