402 
THE VOYAGE OF H.M.S. CHALLENGER. 
have considerable rows of hooks. In structure (PI. XXVa. fig. 4) these hooks resemble 
certain forms dredged by the “ Porcupine ” and procured in Guernsey. There is a pro- 
minent angle for the vibrissse after an interval below the great fang, and in this respect 
the organ approaches Maldane rather than Axiothea. 
Praxilla, Malmgren. 
Praxillahblliheri,^ n. sp. (PI. XLVI. fig. 6; PI. XXVa. fig. 2; PI. XXXVIIa. figs. 3, 8). 
Habitat . — Dredged at Station 174 (south of the Fiji Islands), August 3, 1874; lat. 
19° 6' S., long. 178° 14' E.; depth, 140 fathoms; surface temperature, 77°'0 ; sea- 
liottom, coral mud. 
The anterior region (about nine segments) of a small Praxilla, having a diameter 
of fully 1 mm. 
The most evident distinction from Praxilla prcetermissa is the occurrence of three 
long segments behind the buccal, instead of two. The cephalic plate has a much more 
expanded (almost foliaceous) margin all round. A deep notch occurs anteriorly, the 
centre being filled up by a flattened projection of a blunt conical form. In a lateral 
view (PI. XLVI. fig. 6) the inferior (anterior) two thirds of the foliaceous margin is 
prominent and entire, as well as separated from the rest by a notch. Posteriorly the 
border is less elevated ; and it is also crenated, with a median notch in the centre. The 
foliaceous region presents a row of dots (probably glands) some distance within the free 
edge. The centre of the upper surface of the plate is marked by two grooves, which 
somewhat diverge interiorly (anteriorly), the intermediate ridge being much more acute 
than in Praxilla prcetermissa. Anteriorly the ridge splits, the limb on each side 
merging into the edge of the flat cone. The latter arrangement is indicated in Praxilla 
pratermissa, but is much more pronounced in this form. 
The first three segments have each a single spine of the usual shape interiorly. These 
segments are also considerably larger than the succeeding. Moreover, the anterior margin 
of the next ring (fifth) is produced in the form of a collar which projects forward over the 
posterior part of the fourth segment. This segment (fifth) appears whitish anteriorly as 
in the corresponding one of Praxilla pratermissa, but the latter presents the ordinary 
thickening (in spirit) at the margin and has no collar. 
The hooks (the first row of which are borne by the fifth segment) differ from those of 
Praxilla prcetermissa in having much more elevated crowns (PI. XXVa. fig. 2) and more 
numerous teeth. These organs are smaller than in Maldane and NicJiomache. 
Both cuticle and hypoderm (PI. XXXVIIa. fig. 3) are comparatively thin, and are 
1 After Prof. Kolliker, who, amongst his other heavy labours, wrote on the Annelids of the West Coast of Scotland. 
