84 
THE VOYAGE OF H.M.S. CHALLENGER. 
ventral bristles so well marked, and the same bristles are much longer than in the 
forms mentioned. The ventral cirrus of the present form is decidedly larger than in var. 
gruhei. The dorsum is marked by short brownish bars which are seen through the 
scales. The eyes have slight “ lenses ” in var. murrayi. 
Most papillse occur on the scales and dorsal cirri of Lagisca magellanica, and var. 
murrayi differs from var. gruhei in this respect in having rather longer cilia on the 
dorsal cirri, the basal pedicle of these, moreover, being more distinctly outlined from the 
dilated terminal region. The area of the spines on the outer edge of the scale is limited 
(PI. XIX. fig. 1). 
One of the average dorsal bristles is seen laterally in PI. IXa. fig. 13. Its point is 
somewhat more acute than in Lagisca magellanica, and decidedly more so than in var. 
gruhei. 
The bifid condition of the ventral bristles (PI. IXa. fig. 14) is less marked than in 
var. gruhei, but it comes near Lagisca magellanica in this respect. 
No further information is obtained by an examination of transverse sections of the 
body-wall. 
Lagisca magellanica, var. gruhei (PI. III. fig. 5; PI. XVIII. fig. 2; PI. VIIa. 
figs. 14—16). 
Hahitat . — Several specimens were dredged at Station 145a (off Prince Edward 
Island), December 27, 1873; lat. 46° 41' S., long. 38° 10' E. ; depth, 310 fathoms; 
surface temperature, 41°'5; volcanic sand. 
This form occurred amongst the examples of Polyeunoa levis, and was only dis- 
criminated on minute examination. It resembles the latter in its fine iridescence, its 
pale colour and whitish scales, but differs in having a broader and shorter body, longer 
and more numerous dorsal bristles, both of which, moreover, possess a slightly deeper 
colour. It is interesting to find two from the same ground thus mimicking each other. 
The length of the longest is 38 mm., and its breadth including the bristles 11 mm. 
There are forty -five bristled segments. 
The head (PI. III. fig. 5) has two very prominent points anteriorly. Two eyes, 
widely removed from each other, are situated at the posterior edge, and two, still more 
widely apart, on the lateral prominence, and only partially visible from the dorsum. 
The tentacular base is well developed, but the tentacle is rather short and slender, its 
filiform tip reaching very little beyond the palpi. The antennae likewise have a filiform 
extremity. The tentacular and dorsal cirri agree in shape with the tentacle, but are 
longer. All have a few (i.e., sparsely distributed) short clavate papillae. The ventral 
cirrus reaches beyond the bars of the bristles, and is smooth. The ventral papilla has 
