Lb 
JOURNAL 
OF THE 
ROYAL MICROSCOPICAL SOCIETY. 
OCTOBER 1899. 
TRANSACTIONS OF THE SOCIETY. 
IX. — Notes on some Sponges belonging to the Clionidse 
obtained at Madeira. 
By James Yate Johnson, Corr. M.Z.S. 
(Rea,d 21 st June , 1899.) 
Plate VI. 
The following five forms of boring Sponges were met with, at differ- 
ent times extending over a long series of years, in going over adhering 
masses of Ostrea cochlear and Ghama grgphoides, as well as various 
corals brought up by the lines of the fishermen from deep water off 
the coast of Madeira. The sponges were all examined in the dry 
state. As they appear to be undescribed, I now give the result of my 
examination of them. 
Acca * g. n. 
Spicules of one form only, acerate. 
1. Acca insidiosa sp. n., plate VI. figs. 1 and la. 
Found upon shells of Ostrea and Ghama , lining holes with round 
mouths about 1 • 5 mm. in diameter, and issuing as tubes from them. 
The walls of the tubes are composed of short acerate slender spicules, 
EXPLANATION OF PLATE VI. 
Fig. 1. — Acca insidiosa , part of tlie network of spicules over the end of a tube, and 
part of its wall, x 100. Fig. la, Spicule, x 200. 
„ 2. — Acca rodens , part of the Yvall of a tube, x 200. Fig. 2a, Spicule, x 200. 
„ 3. — Particles of coral produced by the action of Acca rodens , x 200. 
„ 4. — Acca infesta, showing the arrangement of the spicules in the wall of a tube, 
X 100. Fig. 4a, Spicule, x 200. 
„ 5. — Scantilla spiralis , fragment of a specimen with its acerate and spiral spicules, 
X 200. Fig. 5a, Spiral forms, x 300. 
„ 6. — Nisella verticillata, spicules, X 200. 
* Acca, Scantilla, and Nisa are female names to be found in the poetry or prose 
of ancient Rome. 
1899 2 i 
