560 DR. J. S. BOWERBANK ON [Nov. 2, 
traces of any pedicel. In every anatomical character it is in close 
accordance with the type specimen. A portion of this specimen is 
is quite obscured by a crowd of Foraminifera and Polycistina entan- 
gled in the areas of the skeleton-rete. 
The decease of my friend Mr. Deane does not allow of my deter- 
mining the locality of this species with certainty ; but I am strongly 
of opinion that it was collected by Captain Hunter in the West 
Indies, along with Farrea Gassioti and other similar specimens. 
FARREA SPINULENTA. (Plate LXI. figs. 2 & 3.) 
Sponge-mass unknown. Dermis furnished with a quadrilateral 
siliceo-fibrous network, armed at the angles oppositely externally 
and internally with imbricated elongate-conical spicular defences. 
Fibre solid, without canals, minutely spinous; spines acutely coni- 
cal, rather numerous, symmetrically disposed. Dermal membrane 
thin, translucent, abundantly furnished with spinulo-quadrifurcate 
sexradiate stellate retentive spicula dispersed. Interstitial spicula 
large, simple, rectangulate, sexradiate; radii acerate, more or less 
spinous. Sarcode light brown. + 
Colour, in the dried state, light brown. 
Hab. Tripoli (Captain C. Tyler). 
Examined in the dried state. 
The portion of the sponge representing this very interesting spe- 
cies is not quite the eighth of an inch in diameter. It was presented 
to my friend Captain Charles Tyler by Mr. Deane. It was found 
off the coast of Tripoli. The specimen is but a minute portion of 
the dermis of a sponge the mass of which is unknown to us; but 
the nature of the structures displayed by its microscopieal examina- 
tion unmistakably indicates that it belongs to the genus Farrea. 
The quadrilateral siliceo-fibrous network of the dermal rete accords 
in form very closely with that of Farrea occa. ‘The fibres in each 
species are solid ; and, as in F’, occa, the angles of the tissue, both 
externally and internally, are armed with imbricated conical spicu- 
lar defences; but these organs are longer and more slender in their 
proportions than in thoserof F’, occa. 
Thus far they agree very closely in their structures. They differ 
from each other in other important characters. The fibres in F. 
occa are quite smooth, while those in the species under consideration 
are regularly and systematically spinous, forming a very important 
specific character. These spines are not irregularly dispersed ; 
they are disposed in equidistant parallel lines, in accordance with the 
long axis of the fibre, the spines in each line being also at about 
equal distances from each other and opposite the middle of the in- 
tervening spaces of those in the lines on each side of them, so that 
their mode of disposition on the fibre is remarkably symmetrical and 
very characteristic. Other essential differences occur in the dermal 
membranes of the two species. In the quadrilateral, smooth, sili- 
ceo-fibrous network of the dermis of F. occa, described in the Pro- 
ceedings of the Zoological Society of London for March 13, 1869, 
