34 
AUSTRALASIAN ANTARCTIC EXPEDITION. 
Willey (1905, p. 251) found a similar irregularity in H. commensalis. I place 
tlie facts in tabular form for reference :— 
Number of 
Elytron 
in the series. 
Posterior elytra of right side carried by 
the segments in each of the four 
specimens. 
A. 
B. 
C. 
D. 
19 
42 
42 
42 
42 
20 
45 
46 
43 
43 
21 
46 
48 
44 
44 
22 
47 
51 
46 
23 
49 
48 
24 
50 
50 
25 
55 
54 
26 
56 
58 
27 
57 
... 
A is the stained and mounted specimen. 
In B, only 22 pairs of elytra were present, the remainder of the 58 
segments being cirriferous. 
C is soft, and it is impossible to distinguish the elytrophores from the 
cirrophores. 
The elytra, except the first which is circular, are oval with the longer axis oblique 
to that of the body ; and in the better preserved specimens they overlap from side to 
side. The “ areola ” is near the external margin, the surface is smooth, and there is 
no marginal fringe. 
The prostomium (fig. 14) is colourless, broader than long ; the eyes are large, 
the posterior pair far back, latero-dorsal in position, with a large lens ; the anterior 
pair are lateral, with the lens directed forwards ; these are situated at the broadest 
part of the prostomium, which is rather in front of the the middle of its length. 
The prostomium is produced into distinct “ peaks,” immediately above the base 
of the lateral tentacles. The tentacles are smooth, tapering to a point; the median 
is about twice the length of the laterals and longer than the palp. The laterals are 
about | rds the length of the palp. 
The parapods (fig. 15, 16) are short, and distinctly divided into two nearly 
equal lobes. The notopod, of less height than the neuropod, is like it produced into 
a long and slender aciculum-containing process. The dorsal cirrophore overhangs 
the chsetigerous lobe ; the cirrus is smooth, tapering, very long and easily broken off. 
The notopod contains only about 8-10 short yellow straight and stout chsetae 
with extremely fine transverse lines which appear to represent the “pectinated” frills 
of other genera, and these lines in older bristles are often worn away (fig. 20). 
