EEPORT ON THE ANNELIDA. 
19 
since the ventral bristles in the form procured by the Challenger are serrated like the 
dorsal. The size of the eyes also diverges. Further investigation is therefore necessary 
Notopygos labiatus, n. sp. (PL II. fig. 6 ; PL IV, fig. 2 ; PL IIa. figs. 5, 6). 
Habitat. — Trawled at Station 201 (in Basilan Strait, to the south of the Philippine 
Islands), in lat. 7° 3' N., and long. 121° 48' E., in a depth varying from 84 to 102 
fathoms; surface temperature, 83°‘0; bottom — stones and gravel. 
It was accompanied by Polynoe, Eunice, Serpula, and a small Holothurian with long 
ambulacral processes. As further evidence of the hard nature of the ground is the 
occurrence amongst the bristles of fragments of tubes formed solely of sponge-spicules, 
ranged round the wall in a transverse manner or reticulated together to form the 
branched end of the tube {Terebellaf). There were also in the same shelter a few 
fragments of gravel. 
This is a comparatively large form, measuring about 30 mm. in length by 9 mm. in 
breadth, and having the sides and dorsum protected by a dense series of stiff bristles, 
which are pale green throughout. The body has the usual shape, and consists of from 
twenty-five to twenty-eight well-marked segments. On the dorsum a triangular 
brownish area indicates the middle line at each segment-junction. The ventral surface is 
marked by a median line. The head is furnished with a caruncle which extends to the 
posterior part of the fifth body-segment. It is of a deep blackish hue below the inferior 
frills. The lamellae are somewhat lax and spongy, but symmetrically arranged ; the lower 
being very regularly folded and more rigid. The front of the organ is bounded by a 
median and two lateral folds, while posteriorly the pointed tip is formed by a coalescence 
of the transverse plaits. Close to the front of the caruncle is the comparatively short 
median tentacle, while after an interval in front of the head are the two superior 
tentacular cirri, which resemble the former in shape. The inferior are placed on each side 
of the prominent lips. The rounded head lies in front of the caruncle, and has a large 
eye on each side anteriorly, and a smaller, separated by a considerable interval, 
behind. The great oral folds or lips project in front of the head when viewed from the 
dorsum. The hinder part of the mouth is formed by the third body-segment. Posteriorly 
the body terminates in two thick club-shaped processes. 
The branchiae in contraction form small tufts composed of two divisions, viz., a small 
outer and a larger inner. The outer bears a series of pinnae, with occasionally secondary 
pinnae, while the inner, in the form of a miniature bush, likewise shows minor branches. 
All have specks of pigment, so that they are slightly greenish in spirit. In their ordinary 
position in the preparation the main stem is external, the pinnae being directed inward 
toward the middle line. 
The pale greenish dorsal bristles are very prominent, and are large, stiff, and fragle. 
