EEPORT ON THE ANNELIDA. 
385 
The snout is flat, hoof-shaped, with a little dark pigment within the anterior Ijorder. On 
each side a row of eyes runs nearly transversely inward, a short distance behind the tip, 
but they do not meet in the centre. The rows are much less distinct than in the 
British form referred to, and one or two in each case occur behind the main series. The 
branchige have the same proportionally large size as in the British species. 
The bristles do not show any noteworthy peculiarity except that they are short. The 
hooks, again (PI. XXIVa. fig. 11), are decidedly more curved at the tip than in the 
British Cirratulus borealis. 
In this species sections show that while the cuticle is slightly represented the hypoderm 
is thick. The circular muscular coat is fairly developed, but the oblic[ue muscles are 
feeble and the longitudinal ventral groove is not formed. The nerve-area is 
comparatively large. The longitudinal dorsal and ventral muscles are somewhat thin, 
but they have a similar arrangement to those in the typical form. The large ventral 
blood-vessel occurs above the insertion of the oblique, and is distended in all the 
preparations. 
ChcBtozone atlantica, n. sp. (PI. XLV. fig. 8 ; PI. XXIVa. fig. 12). 
Habitat . — Dredged off Sombrero and St. Thomas, West Indies, in 390 and 470 
fathoms. 
The anterior fragment of a peeuliar form, having at first sight the aspect of 
Lumbriconereis. It measures 35 mm. in length, and at its widest part has a diameter of 
4'5 mm. 
The head forms a broad cone without evident eyes. Two small pits, however, are 
present on the dorsum. The mouth opens in the buccal segment inferiorly, and is directed 
forward, while the folds in connection with the aperture are symmetrical. A fissure with 
a closely approximated plait at each side runs forward underneath the snout, while an 
inner and outer semicrescentic fold occur posteriorly, the latter being the longer. The 
body presents the usual flattened appearance of Chcetozone, a marked median groove 
occurring along the ventral aspect, and a slight one along the dorsal surface. 
The dorsal bristles (PI. XXIVa. fig. 12) have the usual tapering structure, and in 
most a series of oblique striae occur toward their insertion, and very minute serrations on 
the edge of the best marked examples. The ventral conform to the same type, some 
being about equal in length, most shorter and broader. Only bristles are present in 
the fragment, which has more than fifty segments. 
Contrasted with those of ChcBtozone setosa the bristles are very much longer and more 
attenuated ; but there is little in them that is diagnostic. The nearest approach to this 
form is one found by the “Porcupine” in the Mediterranean (Station 50), which likewise 
(zooL. chalij. F.xr. — PART XXXIV. — 1885.) LI 49 
