DR. WYVILLE THOMSON ON HOLTENIA. 
719 
sponges with which it is associated. All the mature specimens, however, seemed 
to be in precisely the same condition as those procured last year, and threw no addi- 
tional light upon the structure or physiology of the species. During the past year 
one or two additional species of the genus Holtenia have been observed by Professor 
Oscar Schmidt, along with several other sponges of the vitreous group, among the 
sponges dredged by M. de Pourtales in the Strait of Florida. These species are not 
yet described. 
Description op the Plates. 
PLATE LX VII. 
Holtenia Carpenteri, new genus and species. Natural size. 
PLATE LXVIII. 
Figs. 1,2. The large quinqueradiate spicules of the outer network, x 40. 
Fig. 3. One of the smaller quinqueradiate spicules, from the network of the oscular 
cavity. X 40. 
Fig. 4. A spiny spicule from the margin of the osculum. xl50. 
Figs. 5, 5 « to 5(7. Different forms of the hamate spicules from the fascicles of the 
“beard.” xl50. 
Fig. 6. A small portion of one of the long simple spicules of the “ beard.” X 150. 
Fig. 7. A portion of one of the delicate silky fibres from the neighbourhood of the 
osculum. x 250. 
Figs. 8, 8 a. Fusiform “ spicules of the sarcode,” from the inner part of the sponge- 
substance. X 250. 
Figs. 9, 9 a. Feathered “ spicule of the sarcode,” from the network of the outer wall. 
X 200. 
Figs. 10, 10 a. Spicules of the same type from the wall of the oscular cavity. X 200. 
Figs. 11, 12, 13, 14. Spicules of the same type from different parts of the sponge- 
substance. X 250. 
Figs. 15, 16. “ Amphidisci.” x600. 
PLATE LXIX. 
Fig. 1. Vertical section of the sponge, showing the oscular cavity and the general 
arrangement of the sponge-substance. Natural size. 
Fig. 2. A portion of the cuter wall, showing the stellate arrangement of the siliceous 
spicules, and the ultimate sarcode network with the inhalent pores. X 25. 
Fig. 3. A small part of the same preparation. xl00. 
Fig. 4. A portion of the wall of the oscular cavity. X 40. 
Fig. 5. A part of the same. x200. 
