14 Spong. 
XVII. SPONGI^. 
The next part treats in a comparative way of the colour of the Sponge, 
of the cavity occupied by the Pagurus, and of the vestibule. Next, in 
the genetic part, the origin of the symbiosis is discussed, and also the 
genesis of the vestibule, of colour and shape of the Sponge. The 
last part answers in the affirmative the question : Is there a fixed form 
of Suberites domuncula ? — although only a single instance had come 
under the author’s notice of S. domuncula attaching itself to other 
objects besides Univalves. 
d. Methods op Preservation and Preparation. 
Yon Lendenfeld (25) gives directions for staining collar-cells. 
Maas (30), pp. 334-337, describes his methods for preserving and sec- 
tionizing larvae. 
Vosmaer and Pekeliiaring (63) describe their methods for examining 
the collars of the flagellated cells. 
Weltner (67) gives directions for collecting and preserving Freshwater 
Sponges. 
III. — DISTRIBUTION. 
a. Faunistic. 
Mexico, Campeche : Topsent (57). 
South Carolina: Cliona as enemy of the Oyster ; Dean (9). 
Norway, Trondhjem Fjord : Norman (33). 
Kattegat and Skagerak : Leyinsen (26). 
Germany, Heligoland : Apstein (1). — Holstein, Oyster-grounds : 
Moebius (32). — Neighbourhood of Berlin: Spongillidce ; Weltner 
(66, 67). 
Irish Sea : Brook, &c. (5). 
Jersey ; Hornell (19). 
France, Eaux Blanches, Cette: Gourret (16).— Roscoff : Topsent 
(54). — Mediterranean Coast : chiefly Banyuls : numerous Hexaceratina : 
Topsent (53, 54). — Spongillidce ; Topsent (50). 
Bay of Naples : Tetractinellida : Vosmaer (61). 
Adriatic : Tetractinellida ; Lendenfeld (24). 76 per cent, of all 
Adriatic Tetractinellida have been found at Lesiua, 44 per cent have 
been found in other parts of the Mediterranean, and 24 per cout. out- 
side the Mediterranean. 
Tunis : Gulf of Gabes ; Topsent (56). 
Syria, Lake of Houleh : Spongillidce ; Topsent (48). 
Gulf of Aden, Tadjoura : Topsent (51). 
Sechelle Is. : Topsent (49). 
Australia : Calcarea Heteroccela ; Dendy (13). 
b. Geological. 
Archaic um : Spongice (?) ; Rauff (39). 
Cretaceous, Minnesota: Woodward & Thomas (70). 
