2 Spong. xvii. spongi^:. [1904] 
Page 
F. Miscellanea ^ 10 
(i) Bibliography 10 
(ii) Technique . 10 
(iii) Economics 10 
(iv) Classification . . . . . . . 11 
(v) Chemistry of Sponges . . . . . . 11 
III. Distribution. 
A. Geographical . . 11 
a. Marine 11 
(i) General . . 11 
(ii) Atlantic Ocea.n and Adjacent Seas . . . 11 
(iii) Indian Ocean and Adjacent Seas . . . 11 
(iv) Pacific Ocean and Adjacent Seas . . . 11 
(v) Arctic Seas (vacant). 
(vi) Antarctic Seas 11 
/3. Freshwater 11 
B. Geological 11 
(i) General (vacant). 
(ii) Cainozoic 11 
(iii) Mesozoic 11 
(iv) Palaeozoic 12 
IV. Systematic. 
A. Porifera, general 12 
B. Calcarea (including Astroscleridce) 12 
(i) Homocoela 12 
(ii) Heterocoela 12 
C. Hexactinellida 13 
(i) Lyssacina 13 
(ii) Dictyonina 16 
D. Demospongise . . 18 
(i) Tetraxonida 18 
(a) Carnosa 18 
(b) Tetractinellida 18 
(1) Choristida 18 
(2) Lithistida 19 
(ii) Monaxonida 21 
(a) Hadromerina 21 
(1) Aciculina 21 
(2) Clavulina 21 
(b) Halichondrina 22 
(iii) Keratosa . 25 
(a) Dictyoceratina 25 
(b) Dendroceratina ...... 26 
(iv) Myxospongida 26 
E. Octactinellida (vacant). 
F. Heteractinellida (vacant). 
G. Incertae Sedis 26 
