PROTOZOA. 
676 
A. Hancock (/. c.) does not at all agree with Dr. Bowerbank’s statement 
(in vol. ii. of the ^Monograph of British Spongiadoe/ p. 210) ^^that Mr. 
Hancock has divided Dr. .Johnston’s Halichondria celata into twelve spe- 
cies 5” and states, with regard to these species (described in Ann. & Mag. 
Nat. Hist. vol. hi. 1849, p. 321), that their habits and the characters of 
their spicula are so well pronounced that, with the exception of one, which 
he admits to be a critical species, few naturalists, after a careful examination 
would doubt their distinctness. ]\Ir. Hancock gives many weighty reasons 
for believing that Cliona is the fabricator of its excavated -home, and suffi- 
ciently demonstrates the following facts : — 1. That the sponge, when ex- 
amined in a good state, is always found to fill every part of the excavation, 
even to the remotest ramification. 2. That the excavations are as frequently 
in limestone as in shell. 3. That no worm has been found that can be pro- 
nounced to have made these excavations, and that worms are rarely or never 
taken in them. 4. That these excavations have no resemblance whatever to 
the burrows of worms. 6. That the surface of the excavations inhabited by 
ClioncR is always shagreened or punctured in a peculiar manner, while that 
of the burrows of worms is always smooth. 6. That Clionce with the 
papilloe of the same size, number, and arrangement, and with the same kind 
of spicula, always occupy similar burrows. 7. That the oscula or papillae 
always correspond in size, number, and position to the external orifices in 
the surface of the shell or stone enclosing the sponge. 8. That Cliona has 
been traced through every stage of growth, from the microscopic gemmule, 
adding branch after branch, and lobe after lobe, to the fully-developed sponge 
excavating step by step its complicated abode in sound transparent shell. 
Mr. Hancock refers to a certain relation that appears to exist between 
Cliona and the Foraminifera ; and it would seem as if there were some- 
thing real in the relationship pointed out j for recollecting that the Clionte are 
among the lower organized sponges, their intimate connexion with the Fora- 
minifera is what might be looked for.” 
. Fritz Muller, in a paper on Balanus armatm, Archiv f. Naturg. xxxiii. 
Jahrg. 1. Bd. 1867, p. 330, remarks that this Cirripede lives almost exclusively 
in sponges, one of which would appear to belong to the genus PapiUinaf 
Schmidt. This species (and perhaps, indeed, says Dr. Muller, the entire genus 
Papillina) is but a Vioa ( Cliona), which takes up its abode first in the shell 
or other calcareous body, then, destroying them, grows completely over them, 
forming large cake-like masses, often of a foot or more in diameter, This is 
a very remarkable conclusion. We trust Dr. Fritz Miiller will give some 
further information on the subject. 
Hyalonema, Dr. J. E. Gray (/. c.) believes that bis opinion 
in reference to this genus expressed in 1835 is the correct one, 
viz. that the long siliceous spicules forming the Glass Rope 
constitute the axis, and are the product of a polyp. Dr. 
Bowerbank {L c.) believes that the basal portion of the sponge 
{Carteria, Gray), the glass rope, and the parasitic polyps are all 
portions of the one siliceous sponge. Prof. Max Schultze 
(/. c. p. 153J considers it indubitably established that the long 
threads of the Glass Rope ” are sponge-spicules which termi- 
nate in extremely fine ends in the axis of the sponge, and are 
