POLYCMTA- BENHAM. 
93 
The uncini are uniserial, small, closely-set, and numerous, there being at least sixty 
in one of the posterior lobes. When seen from the side the uncinus presents two teeth 
above the great fang, one large and one small, as McIntosh (1915, p. 29) states for 
T. cincinnatus , there is but a “ single tooth,” “ though occasionally a minute third 
tooth is visible.” I find that when viewed from above the fang is crowned by a row 
of three teeth usually of approximately equal size, and a single minute tooth placed 
eccentrically outside this series ; sometimes two of these minute teeth occur. 
The gland shields number 10-13, they are not at all distinctly defined, being 
rough and traversed by furrows. In T. cincinnatus McIntosh gives 30 shields. I 
looked carefully into this, and found not more than 13 in any specimen. 
The tube, as usual, is membranous, covered with sand-grains of very varied sizes ; 
in some cases they are so coarse as to deserve the name “ pebbles,” so that the outer 
surface is extremely rough and uneven ; in others, the grains are finer and more uniform 
in size and the surface much smoother. Mixed with the sand-grains are fragments of 
brown or green algae, and occasionally portions of Echinid tests. 
Localities .— 
Boat Harbour, 25-30 fathoms. 
Commonwealth Bay, Station C, 15-20 fathoms (very abundant ; bottom rock, 
with small amount of brown algae). 
Distribution, —York Bay, Bucket Island, Magellan Strait (Kinberg) ; Cape Adare, 
S. Victoria Land (Willey). 
Remarks .—According to Be St. Joseph, “ Thelepus ” may have one, two, or three 
pairs of gills. McIntosh says of “ Neottis ” that it differs from Thelepus in 
having three gills, whereas Malmgren’s diagnosis defines Thelepus as having 
two pairs only. Willey, and 1 agree with him, points out the confusion that 
ensues from the wider use of the word ; but modern writers continue to use it 
in this extended sense. It is evident that this large common antarctic form is 
common off Adelie Land, and differs from T. setosus. 
Fauvel has identified T. spectabilis with T. setosus Quatrefages, and in a 
later paper (1917, p. 269), accepting Willey’s suggestion that Kinberg’s species 
is conspecific with the Northern T. cincinnatus , goes even further, and, relying 
on the possibility that in the same species the gills may vary from two to three 
pairs, puts forward the view that the latter may be identical with T. setosus : 
“ Mais ceci n’est encore qu’une simple hypothese.” 
The fact that in dozens of this Southern form, whether it be T. cincinnatus 
or not, there is no sign of any such variation shows that this “ hypothese ” is 
still unproven, and that for the present the two species, T. setosus and 
T. antarcticus (or T. cincinnatus ), are distinct- 
