44 
AUSTRALASIAN ANTARCTIC EXPEDITION. 
Judging from McIntosh’s remarks, a structure that seems characteristic is a sub- 
tentacuiar frontal cone, which he refers to as a “ sub-tentacular cirrus ” though this 
term does not seem altogether applicable to such a short conical process. This “ frontal 
cone ” is situated between the bases of the palps immediately below the median tentacle 
(fig. 37). It is cpiite distinct and separate from the ridge which forms part of the upper 
lip, and appears to spring from the underside of the prostomium itself. When the 
median tentacle is absent, as it is in one of the two individuals, this frontal cone is seen 
projecting beyond the tentaculophore (fig. 36). It is white with a brown base. 
McIntosh refers to this “ remarkable ” organ as being “ unique ” (p. 93), and in this 
place does not refer to any other species except some of the Acoetinao as presenting 
anything like it. Nevertheless on p. 112, in the course of his account of Polynoe platy - 
cirrus he does mention that a small cylindrical boss occurs in the same position. I have 
examined a specimen of this species and can confirm this statement, but it has a spherical 
shape and is by no means so noticeable as in Eulagisca. The use of the word “ unique ” 
seems to suggest that it is one of the generic characters of Eulagisca, especially as he 
gives no diagnosis of this or any of the new genera and sub-genera he had occasion to 
establish. I do not recall meeting with any reference to such a structure in more recent 
works dealing with the Polynoids ; yet it is a structure that is so definite that it may have 
a wider range and be of value irr differentiating some of the species of that puzzling group. 
The ventral surface of the worm is colourless, the electee are pale brown. The 
dorsum is marked with very-pale chestnut brown in the median anterior region, and 
darker on the peristomium. At about frd of the body length, this continuous band of 
pigment breaks up irrto a series of irregular patches which get fainter and smaller till 
about the last quarter, when they die out. 
The prostomium is colourless, though in one specimen it has a crescentic mark 
of dark brown across each half, which is lacking in the other specimen. There is a 
small patch of dark-brown on the upper surface of each of the cirriferous segments just 
within the cirrophore, and in the elytriferous segments a corresponding patch. The 
dorsal cirri have a ring of very pale brown below the subterminal swelling. The anus 
is surrounded by a dark-brown area. 
The prostomium is broader than long, has no peaks, and the three tentacles arise 
in one plane ; the anterior region of each half is continued into the tentaculophore, 
though in the smaller individual, which is less well-preserved than the larger, each half 
of the prostomium appears to lie produced into an internally directed peak; but this is 
due to the oblique line separating it from the lateral tentaculophore. 
The eyes are relatively large, and each is provided with a lens ; the anterior are 
situated laterally about half-way along the prostomial lobe at its broadest part ; the 
posterior eyes are dorsal, about half-way between the anterior eye and the hinder 
margin, though they appear further back in the less well-preserved individual. The 
hinder margin of the prostomium is over-hung by a forward continuation of the peris¬ 
tomium. 
