art 
Fam. 5. 
Fam. 6. 
Fam. 7. 
Fam. 8, 
Systematik. 227 
grains of sand; the other, very slender, at the apex of the 
branches, which do not anastomose. 
Dysideidae. Skeleton formed of reticulated horny fibres with 
sand or spicules of other Sponges imbedded in the centre, and 
covered with a more or less thick coat of horny matter. Brittle 
when dry. 
Chalinidae. Skeleton formed of reticulated horny anastomosing 
filaments, which have one or more series of siliceous spicules in 
the central line. 
Opkistospongiadae. Skeleton netted horny, or expanded skin- 
like fibres, covered with superficial spicules, forming an irregular 
coat, or which are single or grouped, aud divergent from the 
surface. . 
Phakelliadae. Skeleton formed of closely reticulated horny 
fibres, forming an expanded mass; spicules numerous, in bundles, 
forming radiating, repeatedly branched lines, which do not anasto- 
mose on the surface. 
Subsection 2. Spieulospongiae (Spicular Sponges). Sponge fleshy, more or less 
strenethened by fasciculated or scattered siliceous spicules, the 
bundle being sometimes slightly covered with a thin layer of horny 
matter. The sarcode is generally abundant; in some few, as 
Euplectella, it is thin, mucilaginous, and diciduous. 
Urder III. Leiospongia. Sponge-spicules only of one kind, often varying in 
Fam. 9. 
Fam. 10. 
Fam. 11. 
size and shape in the same species. 
Halichondriadae. Skeleton composed of fusiform or pin-shape«l 
spicules variously fasciculated together, or rarely united hy a 
small quantity of horny matter. Sarcode granular or fleshy. 
Polymastiadae. Sponge with tubular fistulous branches; tubes 
open at the end, and formed of longitudinal and transverse fasci- 
cules of fibres. 
Clioniadae. Sponge living and making holes in shells, corals 
and limestone. Skeleton composed of pin-shaped fusiform and 
eylindrical spicules fasciculated together. Sarcode grauular. 
Order IV. Acanthospongia. Spicules of more than one form or kind in the 
Fam. 12. 
Fam. 13. 
Fam. 14. 
same Sponge. 
Euplectelladae. Sponge tubular. Skeleton composed of longi- 
tudinal, transverse and oblique bundles of spicules intersecting 
each other and forming a network. Sarcode mucilaginous, studded 
with many-rayed stellate spicules. 
Esperiadae. Sponge massive. Skeleton composed of fusiform 
and linear spicules, interspersed with anchorate, bihamate, or 
birotulate spicules. Sarcode soft. 
Tethyadae. Sponge sub-globular or massive. Skeleton consisting 
of simple filiform spicules, with three prongs or three recurved 
points at the outer end, and with more or less globular many-rayed 
stellate spicules. 
Subsection 3. Arenospongiae (Sand Sponges). Sponge consisting of a subeircular 
disk of agglutinated sand or siliceous spicula, with a series of 
diverging filiform spicules on the eircumference, and pencils of 
similar spicules on the mouth of the oscules on the upper surface 
of the disk. 
Order V. Arenospongia. 
Fam. 15. 
Xenospongiadae. 
19” 
