520 
THE VOYAGE OF H.M.S. CHALLENGER. 
less distinctly. Two ridges occur on the dorsum between the furrows, and perhaps are 
more characteristic than the latter. 
The branchise are so injured that it can only be mentioned that the radioles are 
peculiarly broad (from within outward), but no wing is present, and there is no opercular 
development in the preparation. 
The anterior bristles have the usual tapering tips and wings, the latter being marked 
by very large serrations. The posterior bristles present the ordinary linear form, with 
a slight curve at the attenuated extremity. 
The anterior (or thoracic) hooks (PI. XXIXa. fig. 28) have a characteristic shape, 
the body being rather long, as indicated by the great length of the dorsal line and the 
prolongation below the great fang. Five or six teeth occur above the latter. An 
inflection exists in the dorsal line. The anterior inferior process or prow is gently cut 
away below the great fang. The posterior uucini show more numerous teeth, and the 
projection of the crown further backward alters the curvature of the dorsal line. 
The body has the usual pair of papillse at the posterior end. 
SeriDiila vermicularis, Linne. 
Habitat. — Dredged in the “Knight Errant,” Station 3, August 3 and 4, 1880; 
lat. 59° 12' N., long. 5° 57' W. ; depth, 53 fathoms, off the island of North Eona. 
Pomatocerus, Philippi. 
? Pomatocerus strigiceps, Morch (PI. LV. figs. 3, 4 ; PI. XXXIa. figs. 26-28). 
Pomatocerus strigiceps, Morch, Naturhistorisk Tidsskrift, Kj0benhavn, June 1863, p. 412. 
Habitat .- — Trawled at Station 167 (in a line nearly opposite the strait between the 
north and south islands of New Zealand), June 20, 1874; lat. 39° 32' S., long. 
171° 48' E.; depth, 150 fathoms; surface temperature, 58°’5 ; sea-bottom, blue mud. 
It was formerly procured off North Australia and New Zealand. 
The length of the specimen (removed from its tube) is 48 mm., with a diameter of 
fully 3 mm. immediately behind the branchiae. The latter measure 9 mm. in length, 
and the oj)erculum and its pedicle 11 mm. 
The branchiae form a dense slightly wavy tuft, with the radioles united interiorly 
by a common web for a third of the total length, and the basal region forms a smooth 
ring. Each radiole is furnished with closely set and rather long pinnae, and the tip, 
which is only slightly tapered, has a short, smooth, filiform process. The extremity 
appears to be more obtuse than in Pomatocerus triqueter, since the pinnae extend freely 
outward as far as the filiform tip. The development of the pigment, moreover, gives 
