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Mr. H. J. Carter’s Contributions 
sponge producing it the name of Corticium Wallichii , con¬ 
jecturing that, hereafter, the latter might be found to belong 
to the Gumminida. (Here I may observe that the charac¬ 
ters of the Gumminida are not absolutely like gum, but like gum 
or glue only when dry, and when wet flexible and insoluble 
like india rubber.) Subsequently, in going through the late 
Dr. Bowerbank’s collections for the British Museum, I found a 
piece of Stylaster , and examining it, under the microscope, 
by chance met with a small excavation in the dead or older 
part, lined with the specimen of Corticium Wallichii above 
described, also a few of its characteristic spicules in another 
part. Finally I found one of the fully developed skeleton- 
spicules in some of the minute detritus which came from the 
root-bunch of the specimen of Euplectella cucumer from the 
Seychelles. Hence Corticium Wallichii may be fairly in¬ 
ferred to exist at least in three distinct localities, viz. the 
South Sea, the Cape of Good Hope, and the Seychelles. 
Owing to the smooth acerate form of the earlier stages of 
development of the skeleton-spicule, it is almost impossible to 
detect the presence of this sponge unless the fully matured 
tubercled spicule or peculiarly shaped flesh-spicule is wit¬ 
nessed. 
Occurring, too, in the midst of the excavations of Cliona 
mucronata , like Samus anonymus , it is difficult to decide 
whether, like the latter, it be a follower of the former, or its 
own excavator, because, as yet, the presence of Cliona mucro¬ 
nata in the same excavation has not been observed. Again, 
Corticium Wallichii has hitherto been found to line the ex¬ 
cavation, instead of being contracted into the centre of it like 
the specimens of Samus anonymus. But both these circum¬ 
stances may be accidental; and therefore nothing but a further 
observation of Corticium Wallichii can determine its real 
nature. The creeping into small cavities is rather a habit of 
the Spongida generally than of any particular species. 
Proposed Names for two new Groups of Flesh-spicules in the 
Spongida , viz. SPINISPIRULA and SCEPTRELLA. 
In my u Notes Introductory to the Study and Classification 
of the Spongida” (Ann. 1875, vol. xvi.), at pp. 30-34 I have 
given a short account of the “ flesh-spicule,” with illustra¬ 
tions of a few of the commonest types, to which I now 
propose to add two more under the names respectively of 
u Spinispirula ” and u Sceptrellaf as a more extended know¬ 
ledge of the Spongida shows this 1o be desirable, if not 
necessary. 
