BIOLOGY. 
Spang. 15 
probably take place over the whole surface of the active cell, but small 
particles seem generally to be absorbed in the space between the flagellum 
and the base of the collar, i.e. at the apex of the funnel formed by the 
collar. Hence the most perfect chambers are those which possess a 
Sollas’s membrane; Cotte (8). 
(iii) Respiration. —Vacant. 
(iv) Secretion and Excretion.— Catabolic products of Suberites 
domuncula : precise determinations not obtained, but it is shown that 
nitrogen is excreted by sponges “sous forme d’ammoniaques composees;” 
Cotte (9). 
(v) Irritability, Contractility, etc. —Vacant. 
(vi) Individuality.— Haller (17) p. 68. 
(vii) Miscellanea.—Experimental Physiology. —Nothing. 
D. Bionomics. 
(i) General Accounts.—Vacant. 
(ii) Special Habits.—Perforation of rocks, etc., by Cliona vasti- 
fica: the “cellules spheruleuses” send out protoplasmic processes which 
pass through the intercellular gaps in the flat epithelium, penetrate into 
the solid substance, and detach “lunules” of calcareous matter. Although 
no acid secretion was detected, it probably takes place, and there is 
perhaps also the action of a ferment: the action of the “ cellules spheru¬ 
leuses ” is analogous to that of osteoclasts in higher animals; Cotte (7). 
(iii) Habitat. —Relations to habitat of Sycon compressum [Grantia 
compressa ], Halichondria panicea, and Suberites domuncula ; Bidder (4).— 
Habitat of Astrosclera willeyana Lister; Willey (70) p. 733. — Habitats 
and mode of occurrence of Hexactinellida in the Indian Ocean ; Alcock (1) 
pp. 146, 153 & 294-296.—Habitat of Ccirterius stepanouri Dyb.; Lauter- 
born (32) pp. 532-534. — Ephydatia fluviatilis occurring in sea-water; 
Levander (35) p. 9. 
(iv) Defence and Protection, Mimicry.—Experiments on the 
endurance of Sycon compressum [Grantia compressa] under exposure: the 
spicules, especially the cortical layer of club-shaped radial monaxon 
spicules, probably serve to check evaporation, and to enable the sponge 
to resist the entrance of rain-water, when exposed on the rocks at low 
tide: the flattened, compressed form prevents the formation of an air- 
bubble in its gastral cavity as the result of such evaporation as still takes 
place; Bidder (4) pp. 376-380. 
Significance of colours in deep-sea sponges; Nutting (44 ).—Boris 
johnstoni mimicking Halichondria panicea ; Lebour (33) p. 171._ Chon- 
drocladia “shows a remarkable protective resemblance to a bleached 
skeleton of a gadoid fish;” Masterman (41) p. 110. 
(v) Enemies of Sponges.—Vacant. 
(vi) Parasitism and Commensalism.—A Hermit Crab (Can- 
cellus spongicola , n. sp.) inhabiting a sponge; Benedict (3) pp. 773 & 774, 
figg. 3 & 4.—Association of Hyalonema with Palythoa , and of H. masoni 
F. E. S. with Scalpellum squamuliferum and with Richardina , sp. ; 
Alcock (1) pp. 295 & 296, fig. 96, and p. 273.—Cirripedes (Scalpellum 
squamuliferum and Megelasma carino-dentatum) replacing the Palythoa- 
crust on the peduncle of Hyalonema masoni F. E. S. ; Schulze (56) p. 14. 
