34 



AUSTRALASIAN ANTARCTIC EXPEDITION. 



Willey (1905, p. 251) found a similar irregularity in H. commensalis. 

 the facts in tabular form for reference : 



I place 



Number of 

 Elytron 



Posterior elytra of right side carried by 

 the segments in each of the four 

 specimens. 



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 chaetigerous 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). 



