1869.) DR. 5.5. BOWERBANK ON SILICEO-FIBROUS SPONGES. 8) 
while others appear to have no connexion with the tissues beneath 
them. 
Dacty.Locatyx Pratti, Bowerbank. 
Sponge irregularly cup-shaped, pedicelled ; surface even, slightly 
undulating. Oscula simple, small, dispersed, numerous. Pores 
congregated in areas formed by the distal terminations of the ex- 
pando-ternate connecting spicula, numerous and large. Expansile 
dermal system—dermal membrane pellucid, furnished abundantly 
with minute entirely spined fusiformi-cylindrical spicula, short, 
frequently semilunate or angulated, irregularly dispersed. Con- 
necting spicula irregularly fureated patento-ternate; radii slightly 
depressed, apices thin and expanded; ternate heads combining to 
form a dermal network. Enveloping membrane of the rigid skeleton 
abounding with the same minute spicula as those of the dermal 
membrane, and also with numerous separate flat fasciculi of long 
and slender acerate tension-spicula. Skeleton—rete compact ; 
fibres smooth, or irregularly and slightly spinous ; free terminations 
of fibres ramose, or abundantly tuberculated. Interstitial spicula 
acerate, long, slender, and frequently flexuous, mostly disposed in 
lines at right angles to the dermal surface. Interstitial membranes 
pellucid, furnished with the same form of retentive spicula as the 
dermal membrane. 
Colour in the dried state, light brown. 
Hab. East-Indies (8. P. Pratt, Esq.) ; off the island of Formosa 
(Mr. Swinhoe). 
Examined in the dried state. 
I am indebted to my late friend Mr. S. P. Pratt for the very in- 
teresting specimen under consideration. He stated that he was not 
quite certain of its locality, but he believed he had received it from 
his son, who was then in India, along with many other interesting 
marine specimens. The form of the sponge is that of an irregularly 
shaped cup, the rim of which is nearly an oblong, 44 inches long and 
33 inches wide ; and at one corner there is a depression of the mar- 
gin, so as to form a lip to the cup of rather more than an inch in 
depth. The height of the cup in its present state is 4 inches. It 
has been broken away from its natural base ; but, from the indications 
remaining, it is probable that it was elevated on a short pedestal. 
The margin of the cup is unequal in its thickness, varying from half 
an inch to a thin sharp edge. The specimen was evidently in a living 
state when taken from the sea, and it is still in an excellent state of 
preservation. 
The oscula are simple orifices, without any especial defensive or- 
gans ; they have the usual contractile membrane to Open and close 
them in accordance with the necessities of the amimal, The greater 
portion of them were closed, while others were more or less open. 
Through one in the latter condition, in a slice from the surface 
mounted in Canada balsam, the surface of the rigid skeleton was 
seen, covered by the enveloping membrane, which was closely adhe- 
