28 
THE VOYAGE OF H.M.S. CHALLENGEE. 
shorter than the foregoing cirri. The caruncle shows a dorsal ridge, indistinctly 
separated from the horizontal basal portion, and thus decidedly different from that in 
Hermodice. The larger pair of eyes is situated in a line with the anterior margin of 
the tentacle, and the smaller a short distance behind. The four mark out an oblong, 
probably nearly a square in life. 
The mouth opens on the ventral surface at the anterior border of the fourth body- 
segment, the central region in front being occupied by the wedge-like lobes which pass 
forward to form the snout, and the sides by the convergent lines of the three anterior 
body-rings. The anus occupies the dorsum of about three of the small terminal 
segments, and has posteriorly a prominent papilla. In the intestinal canal of specimens 
from the Seychelles are masses of algse and considerable pieces of coral and nuUipore. 
In the present case pieces of olive-brown sea- weed are most conspicuous. 
The branchiae commence on the second body-segment each as a tnft of two processes. 
They are continued along the dorsum as somewhat less conspicuous organs than in 
Hermodice. When fully formed each tuft consists of a series of slightly divided processes, 
chiefly after a dichotomous type. They are continued to the last or the penultimate 
segment. A peculiar infusorial parasite occurs in numbers on the branchiae. 
The dorsal bristles consist (1) of a few simple distinctly curved bristles (PI. IIIa. 
fig. 5), which are frequently alisent in the preparations ; (2) of a large group of charac- 
teristic bristles with slightly bifid tips (PI. IIIa. fig. 6), one of the divisions being a mere 
spur, while the other is extremely elongated and tapering, with serrations along the 
inner edge ; and (3) of a well-marked serrated series (PI. IIIa. fig. 7), vdth the terminal 
portion striated in a peculiar manner. 
The ventral bristles are bifid, one or two superiorly (PI. IIIa. fig. 8) having slender 
shafts and very long tips, with serrations on the inner edge ; while the majority have 
stout tips (PI. IIIa. fig. 9) with three or four serrations on the inner margin. Anteriorly 
the tips of these bristles are somewhat longer. Amongst the inferior bristles are some 
short simple spines with a dilatation in the centre (PI. IIa. fig. 13). Similar forms are 
also shown by Kinberg in Eurythoe corallina} These hastate spines have the tips 
projecting only a short distance beyond the cuticle, the stoutest part of the bristle being 
internal. 
The dorsal cirrus has the usual basal segment, and though fairly developed does not 
project quite as far as the bristles. It becomes more elongated jDosteriorly. The ventral 
is a short process in the ordinary position. 
The arrangement of the nerve-trunks differs from that in CJdoeia, since the oblique 
muscles decussate beneath them. In some sections (anterior) a regularly arranged 
series of longitudinal fibres occurs within the circular muscular layer, so that the nerve- 
cords are carried further inward at these points. 
1 Freg. Eugen. Resa, Tab. xii. fig. 12. 
