2 Spong . 
XVII. SPONGIA:. 
Page 
d. Bionomics ......... 15 
(i) General Accounts (vacant). 
(ii) Special Habits . . . . . . . 15 
(iii) Habitat ..15 
(iv) Defence and Protection, Mimicry . . . 15 
(v) Enemies (vacant). 
(vi) Commensals and Parasites . . . . . 15 
(vii) Sponges as Geological Agents, Fossilization . 16 
e. Reproduction and Development . . . . . 16 
(i) Germ-Cells, Fertilization . . . ... 16 
(ii) Embryology . . . . . . . . 16 
(a) General Accounts . . . . . 16 
(b) Early Stages, Larvae, and Metamorphosis 16 
(c) Post-Larval Development, Organogeny (vacant). 
(iii) Asexual Reproduction.16 
(a) Fission and Vegetative Budding . . 16 
(b) Germinal Budding and Gemmule-For- 
mation . . . . . . 16 
(c) Regeneration (vacant). 
f. Miscellanea . . . . . . . . . 17 
(i) Technique . . . . . . . . 17 
(ii) Economics . . . . . . . . 17 
(iii) Bibliography. . . . . . . . 17 
III. Distribution. 
a. Geographical ......... 17 
a. Marine .......... 17 
(i) General. ........ 17 
(ii) Atlantic Ocea.n and Adjacent Seas . . . 17 
(iii) Indian Ocean and Adjacent Seas . . . 17 
(iv) Pacific Ocean and Adjacent Seas . . . 18 
(v) Arctic Seas (vacant). 
(vi) Antarctic Seas . . . . . . . 18 
(3. Freshwater ......... 18 
(i) Europe ......... 18 
(ii) Asia.18 
(iii) Africa ......... 18 
(iv) Australian Region (vacant). 
(v) America . . . . . . . . 18 
b. Geological.18 
(i) General.18 
(ii) Cainozoic.19 
(a) General (vacant). 
(b) Pleistocene (vacant). 
(c) Pliocene . . . . . . . 19 
(d) Miocene . . . . . . . 19 
(e) Oligocene (vacant). 
(f) Eocene (vacant). 
