1869.] DR. J.S. BOWERBANK ON SILICEO-FIBROUS SPONGES. 87 
exhalant surface; simple or slightly elevated and marginated. Pores 
inconspicuous, evenly dispersed on the outer or inhalant surface, 
furnished with a protective fringe of minute short acerate spicula. 
Expansile dermal system—dermal membrane abundantly furnished 
with minute, short, stout, acerate spicula, evenly matted together. 
Connecting spicula foliato-expando-ternate ; foliations of the apex 
depressed, very elaborate and irregular, shaft rather long. Skeleton- 
surface covered by a secondary dermal membrane ; abundantly fur- 
nished with minute, short, acerate spicula, same as those of the pri- 
mary dermal membrane. Skeleton-fibres somewhat compressed, 
smooth, furnished at intervals with groups of large spicular attenu- 
ated spines. Sarcode in the dried state amber-coloured. 
Colour, in the dried state, nut-brown. 
Hab. St. Michael’s, Azores (Robert M*Andrew, Esq.). 
Examined in the dried state. 
This sponge was described by Dr. J. E. Gray in the ‘ Proceedings’ 
of this Society for 1859, p. 438, plate xv. Radiata, under the 
name of Macdndrewia azorica. In its external appearance it very 
closely resembles Dactylocalyx heteroformis of the Museum of the 
Jardin des Plantes, Paris, and Dactyloealyx Prattit; but in its 
structural characters it differs in many important respects from 
either of them. 
The structure of the skeleton is truly that of a Dactylocalyz, and 
I have therefore referred it to that genus. 
The description of the genus in the ‘ Proceedings’ of this Society 
for 1859 refers only to its external characters, and is so vague that 
it might be equally well applied to several other species of this 
tribe of sponges. In the ‘ Proceedings’ for May 1867 Dr. Gray 
gives another version of its generic characters, in which he designates 
the sponge as a coral, thus:—‘‘ The coral expanded, cyathiform ; 
the upper and lower surface smooth, the upper surface with small 
oscules; the fibres of skeleton small, with stellate spicules on the 
dermal surface. The stellate spicules three-rayed ; the rays forked 
and reforked. Bowerbank, British Sponges, fig. 53.’? This de- 
scription is not only quite as vague as the original one, but, in addi- 
tion, is very incorrect. In the first place, the specimen is undoubt- 
edly not a coral; and, secondly, there are no stellate spicula on the 
dermal surface, nor have the connecting spicula ‘‘ the rays forked and 
reforked.’? And the reference made to ‘ British Sponges,’ fig. 53, 
is a mistake, as a reference to that work will prove, the spiculum 
there represented by the figure quoted being ‘“‘a spiculated dichotomo- 
patento-ternate ” one ‘‘from an unknown sponge.” And, moreover, 
no such form of spiculum is to be found in Dr. Gray’s Mac Andrewia 
azorica. The specimen is in the British Museum. 
The sponge is elevated on a short stout pedicel, from the top of 
which it expands into an irregular sinuously shaped cup with rounded 
margin. The external or inhalant surface is smooth, but slightly 
-undulating. The internal or exhalant surface is slightly roughened 
by the presence of the oscula, which are evenly distributed over the 
