BIOLOGY. ' Spong. 9 
several small chromatin -granules (nucleoli). A well defined endoplas- 
matic layer surrounds the nucleus. 
According to Lendenfeld (21) the ova of Vioa vastifica possess pseudo- 
podia and a largo nucleus with a tangled chromatin thread. 
Lendenfeld (21) describes groups of granular cells in the cortex of 
Tethya which are probably young buds. 
i. Physiology [cf. Title 21]. 
The fact that the surfaces of boring sponges in contact with the stone, 
shell, etc., in which they live, are covered with semispherical protuber- 
ances fitting into corresponding pits of the stone, etc. appears, according to 
Lendenfeld (21), to bo in favour of Letellier’s theory concerning the 
boring action of sponges. 
k. Habits, Bionomics [cf. Titles 20, 21]. 
The great differences observed in the structure of the surface in Vioas 
and Papillellas are, according to Lendenfeld (21), to a great extent merely 
due to differences in the degree of retraction of the papillae. When these 
are extended, the sponge-surface appears highly papillous ; when they are 
retracted, honeycombed. 
Several species of Vioa and Papillella occur, both as free and as boring 
forms. It can hardly be doubted, thinks Lendenfeld (21), that many, if 
not all, boring sponges are able to grow out in the form of a free sponge, 
which may attain a very large size ( Vioa [ Rapliyrus ] liixoni ), after having 
destroyed the stone, shell, etc. which they originally attacked. 
Several cases of Symbiosis were observed by Lendenfeld (20, 21). The 
specimens of Phyllospongia dendyi var. spiculifera examined contained 
numerous Oscillarian Algse (20). Stelospongia opercxdum appears to grow 
on an ascidian and to cover its mouth with a moveable lamellar outgrowth 
(20). Ficidina ficus has the same habit of growing on shells inhabited by 
a hermit crab, as Suberites domuncula. In both the entrance to the 
cavity of the shell always remains open (21). Numerous commensals, 
Hydroids, Worms, etc. (21) live in Suberites domuncula. The varieties 
of Suberites fugax contain three kinds of symbiotic plants, Beggiatoa. 
2. GEOGRAPHICAL DISTRIBUTION. 
A. General [cf. Titles 4, 12, 19, 21, 40]. 
Breitfuss (4) draws attention to the poverty of tropical seas in Calcareous 
Sponges. In lat. 30° S. and N. the Calcarea become more numerous and 
from thence they constantly increase in numbers towards the poles. 
Gunther (12) mentions the abundance of Sponges on old cables from 
Abyssal depths. 
Lendenfeld (19) considers the Rockall-Sponge fauna nearly allied to 
the British. 
Lendenfeld (21) states that of 30 Adriatic species of Clavulina only 
10 have been found in the Mediterranean outside the Adriatic, but 20 
outside the Mediterranean. This shows how little is known of the extra- 
Adriatic, Mediterranean sponge fauna. 
Of the six species of Spongillids found in Eastern Africa only one, 
according to Weltner (40), has also been found in other parts of the 
world. 
B. Faunistic [cf. Titles 1, 2, 3, 4, 5, 8, 10, 11, 13, 14, 17, 19, 20, 21, 
22, 24, 27, 31, 37, 38, 40, 41], 
Continent of Europe. — Fric & VIvra (10) mention two species of Spon- 
gillids from Bohemian lakes. — Garbini (11) found spicules of four species 
