312 
THE VOYAGE OE H.M.S. CHALLENGEK. 
A remarkable condition exists in one of the larger forms (in a tube covered by 
Glohig evince), for the entire dental apparatus, with the exception of the mandibles, is soft 
and pale, so as to resemble a Crustacean shell after ecdysis. The latter jDrocess, however, 
has hitherto been unknown in this group. The tips of the maxillae are boldly curved 
and very flexible, and the posterior part is much flattened. The first tooth of the left 
great dental plate is characteristically elongated, but its soft condition causes abnormal 
curvatures. A black line occurs between the maxillae and the jDosterior processes, 
which are separated by a considerable interval. There is nothing in the appearance of 
the Annelid denoting such a change, and the mandibles are quite dense. 
The first foot bears a series of bristles (PI. XXIa. fig. 19), characterised in the older 
specimen by a somewhat blunt and large terminal process, beneath which is a small 
tooth that likewise is blunt, probably from wear. In younger forms a more perfect 
condition of the tip is noticeable (PI. XXIa. fig. 20), both as regards the bifid process 
and wing. An oblique line near the tip j^robably indicates a rudimentary articulation. 
The feet in general (PI. XL. fig. 7) are similar to those of Nothria concliylega, but 
the accessory and other ventral cirri in front are less conspicuous. Anteriorly the entire 
foot,' moreover, is less produced, especially the setigerous region, while the bristles are 
much longer. The dorsal bristles (PI. XXIa. fig. 21) are more delicately “ winged ” 
than in the common form ; and the brush-shaped kind (PI. XXIa. fig. 22) are propor- 
tionally broader at the tip. 
The hooks again (PI. XXIa. fig. 23) differ considerably in the curve at the end of 
the shaft, and in the nature of the bifurcation. The distal fang is more elongated and 
less robust than in the European form. Two or more occur in each foot. 
The absence of branchise further distinguishes the present species from Nothria 
conchylega, and the body is much more friable than in the latter. 
The posterior feet present near the base on the dorsum a prominent papilla 
anteriorly and another posteriorly, apparently connected with the body cavity. In this 
region also the spines of the feet are more prominent, and the lower fang of the hook larger. 
On the ventral surface a central prominence in each segment occurs behind the 
anterior third. 
The tube formed by this species is somewhat flaccid, flattened, and nearly opaque. 
It is supported along each edge by the long glassy spicules of a Hexactinellid Sponge 
(PI. XL. fig. 5). The tip of the spicule projects considerably (7—9 mm.) at each end of 
the tube, but on opposite sides, as shown in the figure. The tube measures about 58 
mm., and is quite straight. In structure it is thus intermediate in position ■ between 
Hyalincecia and Nothria, being devoid of the rigidity of the former, and the abundant 
extraneous bodies of the latter. One of the larger tubes is covered with Globigerinw, 
and with a single long spicule at the side. Another has a few Glohigerince scattered 
over a wall composed of greyish mud, and strengthened by a long spicule passing from 
