404 Mr. J.S. Bowerbank on the Spongiade, 
brane, thickly overspread with minute semi-opake granules : such 
is its appearance in specimens which have been preserved i in spirit 
immediately on being removed from the sea ; but after havmg been 
dried, the membrane and its granulated coat is usually fractured 
in every direction, and then presents an appearance as if the cavity 
were lmed with irregular, minute flocculent masses, or the mem- 
brane separating from the surface of the canal may ‘be seen repo- 
sing in it in the form of a contracted tube. Portions of it may 
also be occasionally seen projecting from the fractured ends of 
the fibres, especially in the examinations of dried specimens. 
I have been unable to detect any communication between the 
great central cavity and the outer surface of the fibre, the pro- 
jecting ends of which are always naturally hermetically sealed. 
I have been favoured by my friend Dr. Veronge with a very 
beautiful species of this genus which was immersed in spirit im- 
mediately on being removed from the sea, This specimen is in 
the form of a cluster of cylindrical tubes about twelve mches in 
height and two in diameter, the thickness of the tube being about 
half an inch. 
The whole of the external and internal surface of the sponge 
is closely covered with a strong investing membrane, and I have 
observed the remains of a similar tissue upon several other dried 
species of this genus in my possession. In all the cases the mem- 
brane was simple in structure, semi-opake, and had the internal 
surface abundantly furnished with tessellated cellular structure. 
The interstitial fleshy matter of the specimen presented to me 
by Dr. Veronge exhibits a high degree of organization. When a 
section was made at right angles to the axis of the sponge, it cut 
as firmly, and presented as close a texture as a section of the 
liver of a quadruped does. 
When minute fragments were examined by transmitted light 
and a microscopic power of 300 linear, it was found to consist of 
closely compressed tessellated cellular structure, varying some- 
what in its general aspect in different parts of the specimen, but 
in the best-defined portions it presented the appearance repre- 
sented by Pl. XIII. fig. 8. 
A few minute vessels were observed in the most transparent 
portions of this tissue meandermg amid the cells, but in other 
species in which portions of the remains of the interstitial fleshy 
matter were found, they were observed to exist in a much greater 
abundance. 
I have been unable to detect more than a few accidental spi- 
cula in the investing membrane of any of this family, and I be- 
heve that they do not naturally exist im any part of any one of 
the species of this group. 
The Verongie have existed at former periods in great abun- 
