676 
THE VOYAGE OE H.M.S. CHALLENGER. 
“ Of a H the deep-water genera, Fcirciminaria appears to be the most exclusively 
abyssal, and the accompanying figures of species belonging to that genus (figs. 225 to 229 ) 
are given as types of the delicate and flexible con- 
formation of the forms inhabiting the tranquil depths 
of the ocean. 
“ From the Tables it will be seen that the geogra- 
phical distribution of the very deep-water forms has 
no evident relation to the bathymetrical. And in even 
still less degree is any evidence afforded respecting 
their distribution in time as might indeed be expected 
from the exceedingly delicate and fragile structure of 
all or nearly all the species, excepting one of very 
peculiar habit, Cellepora solida, which bears a very 
close resemblance to, if it be not identical with, the 
Miocene Celleporaria polythele, Manzoni , 1 (nee Reuss).” 
Cephalodiscus. — Professor MTntosh furnishes the 
following note on this remarkable form : — 
“ No more interesting or more novel type occurs 
in the series of discoveries by the Challenger than 
Cephalodiscus, a new Polyzoon allied to Professor' 
Allman’s Rhabdopleura. This form, which has been 
termed Cephalodiscus dodecalophus , 2 was dredged in 
the Strait of Magellan in 524 fathoms, and the Poly- 
zoarium at first sight may readily be mistaken for a 
seaweed, since it is composed of a much branched 
fucoid tissue tinged of a pale brownish hue, and 
semi-translucent (fig. 230 ). It is spinous all over, and moreover has numerous apertures 
leading into the interior, which is honeycombed by a series of canals through which 
sea water has constant ingress and egress. This remarkable coenoecium, which is 
secreted by the little animals, has probably been found that best adapted for the 
preservation of the species, by its resemblance on the one hand to other organisms in its 
neighbourhood, and on the other hand by its affording complete aeration, abundant supply 
of food, and security to the little polypides and their delicate plumes. The polypides 
are quite free and in great profusion ; moreover, the caudal region has buds, and in addi- 
tion free ova occur in numbers. Each adult polypide (fig. 231 ) is about 2 mm. in length, 
with a bean or kidney-shaped body, from the posterior bulbous part of which a pedicle 
Fig. 229. — Farciminarici, brasiliensis, Busk. 
a, natural size; b, magnified ; c, ooeeium, more 
highly, magnified. 
1 I Briozoi Eossili del Miocene d’Austria ed Ungheria, p. 4, pi. i. fig. 3, 1877. 
2 Ann. and Mag. Nat. Hist., ser. 5, vol. x. p. 337, 1882. 
