358 SIE SIDNEY F. HARMBR ON 
and D. Rootlets not forming marginal bundles, some of them given off 
by basal heterozooecia. Each zooecium is typically provided with frontal and 
marginal avicularia and with a basal vibraculum, the last at its proximal end, 
the marginal avicularium at its distal end. Cavity of the vibraculum 
divided by a calcareous septum into a larger chamber containing the muscles, 
and a smaller chamber, from which a rootlet originates in the proximal 
members of the colony at least. Seta of the vibraculum without lateral 
branches. 
This genus is readily recognizable, and as but little confusion exists with 
regard to its limits, I do not think it necessa7-y to discuss the species in detail. 
The relations of the joints to the outer zooecia at the bifurcations give useful 
assistance in characterizing species ; a point which will be brought out more 
fully in my forthcoming ISiboga Report. In some cases, as in fig. 8, the 
joint traverses the opesia at its middle. In other cases it merely involves the 
proximal end of the opesia ; and in others it passes entirely on the proximal 
side of that opening. 
Kluge (1914) has described 17 species which he refers to Scrupocellaria. 
One of these, S. berthoUetii, Aud. (p. 616) is from Cape Verde, and is rightly 
placed. The remainder are from Kerguelen (1 species) and Antarctic 
localities (15 species). All of these may more properl}^ in my opinion, be 
distributed among the genera Amastigia, Notoplites, Menipea, and Tricellaria, 
and I think it has still to be proved that the genus occurs within the limits 
of the Antarctic Circle. Scrupocellaria is a characteristic genus of Northern 
latitudes, it is well represented in' the Siboga Collection from near the 
Equator, and it is well known to occur in localities much further south, as for 
instance off the south coast of Australia. Its possible relation to Amastigia 
is indicated on p. 337, under A. Jdrkpatricki. 
Although Scrupocellaria exhibits the tendency, shown in other members of 
its Famil)^ to suppress important structures like the scutum and the frontal 
and marginal avicularia, all these structures are more commonly retained 
than in certain other genera. The basal vibracula are Yery rarely wanting ; 
and in most cases they occur regularly on every zooecium. The occurrence 
of either one or two vibracula in the axil of the bifurcation is a useful 
systematic character, as has been pointed out by Waters (1897, J. L. 8. xxvi, 
p. 7). Levinsen (1909, p. 134) has stated that the vibraculum of Scrupo- 
cellaria is not divided into two chambers. I do not understand this assertion, 
which is at variance with my own results. 
