REPORT ON THE ANNELIDA. 
319 
tRe various plates are almost identical in number. Ventrally the dental surface of the 
mandible (Fig. 75) presents a somewhat petaloid appearance, the anterior external augle 
being much produced and pointed,, and the cutting edge is slightly denticulated. More- 
over, the outer margin is marked by a shoulder or projection at the point where a nearly 
transverse ridge indicates a thickened plate covering the posterior moiety. A slight 
band of dark pigment occurs along the posterior margin of this dental surface. The 
separation of the special dental process from the end of the shaft is well seen on the 
dorsal surface. The dental region of the mandibles of those from Station 299 varied in 
regard to the posterior raised plate, and the anterior denticulations. The dental 
apparatus is thus on the whole closely allied to that of the previous form, one of the 
most evident distinctions, however, being the larger angle formed by the posterior 
appendages with the maxillae. 
The anterior dorsal cirri are shorter and stouter than in Nothria abranchiata. 
Moreover, at the seventeenth foot a thickish branchial process makes its appearance, 
and continues a considerable distance, but not to the posterior end of the Annelid. The 
first ventral cirrus is enlarged and lobulated, and the second still more so, while the 
third forms a flattened scute-like process. 
So far as examined, the bristles of this form and Nothria abranchiata approach 
each other very closely, and upon this ground difficulty was at first experienced in 
separating them. A closer examination, however, showed that the hooks toward the 
twentieth foot in this species have shorter limbs to the fork (PI. XXIIa. fig. 5), and the 
curvature at the tip differs. 
The bristles of the first foot present a blunt hook at the tip (PL XXIIa. fig. 4) with 
a process beneath. The curve of the distal region is bow-like, and the central striae are 
oblique throughout a considerable distance. 
The lateral regions of the posterior segments are marked superiorly by curious pro- 
jecting folds. Two long caudal cirri occur beneath the corrugated anus. 
The faecal pellets are very firm. In the specimens from Station 298 they consist of 
a tenacious greyish mud in which are a few Foraminifera, minute spicules and micro- 
scopic ovoid bodies. In those from Station 299 the pale brownish masses of mud 
showed fragments of minute Crustacea and Foraminifera. 
The tubes are flattened dark greyish structures, consisting of a basis of chitinous 
secretion coated with mud, and strengthened both dorsally and ventrally by long- 
cylindrical brownish tests of Foraminifera, and a few white tubes pertaining to the 
Serpulidse. These tubes range on each side of 140 mm. in length, and have a diameter 
of about 12 mm. at their wider portions. They are often flattened, indeed their 
posterior end is generally so. Some have various parasitic Polyzoa attached to them. 
They are frequently marked by numerous transverse ridges of chitin, projecting 
through the mud. In a few the front of the tube has fragments of shells and other 
