50 W. G. RIDEWOOD. 
to suspect that one of them is a parent colony of the others. It is further of 
interest that, although these colonies appear so young and so recently established, 
there are present, attached to the interior of the test, numerous solitary eggs 
of oval shape, small size (averaging 42 by ‘47 mm.) and pale yellow colour. They 
are affixed by a short, fine, transparent pedicle continuous with the thin enveloping 
membrane. 
All the specimens were preserved by being placed in 70 per cent. alcohol. 
Tubarium. 
The tubarium of this species in its present state, after being in alcohol for three 
years, is of a light brown colour. It is larger than that of Cephalodiscus dodecalophus, 
has shorter and more closely-set branches, and thicker and longer spines. 
The largest piece (fig. 1, B, plate 2) measures about 110 mm. by 70 mm. The 
original label accompanying this piece is marked “Has been dry.” A smaller piece 
which was dredged at the same time (fig. 1, A), and which in all probability is part of 
the same colony, is free from this disadvantage, and does not show the shrivelling of 
the tips of the spines which is apparent in specimen B (as also in C). 
The cavity occupied by the polypides is continuous throughout, and branches 
regularly with the branching of the tubarium. In fig. 22, plate 4, is given a 
diagrammatic representation of the cavity of the tubarium, as though the polypides 
had been removed, a cast made of the interior, and the tubarium subsequently 
stripped off. Sections taken through the stems and branches of the colony are roughly 
elliptical in shape, and measure about 6 by 4 mm. across. The width of the interior 
of the tube is from 2 to 4 mm., but it is greater where a branch becomes flattened, 
as it frequently does towards its free extremity. 
The wall of the tube is thinnest in those parts where the test is most regularly 
tubular, and where there are no spines. The thickness here is not more than *3 mm. 
In the basal parts of the colony the tubarium is more massive, and in places attains 
a thickness of 2 or 3mm. Although the lumen varies in diameter in the manner 
described in the preceding paragraph, the inner surface of the tubarium is smooth 
and even, and is not irregularly chambered as it is in C. dodecalophus. There are 
no internal trabeculae, ridges or partitions ; and the cavity is continuous from one 
end of the colony to the other. The rooted end is, of course, blind, but there are 
several short branches with ostia close around it. 
The terminal branches are short, about 10 to 13 mm. in length, and the portions 
of the relatively main stem between two consecutive branches are rarely more than 
10 mm. in length, frequently much less. 
The openings of the tubarium, the ostia, are situated at the terminations of the 
branches, and are one, two or three in number at the end of each branch. This rule 
that the openings are terminal is not without exception, but most of the instances of 
