SPONGIA. 
8 Spong. 
Polejaeff (28), after a full discussion of the characters which are of 
systematic value in the classification of the Keratosa , adopts provisionally 
and with modifications Yosmaer’s method. In the concluding part of the 
Report, however, he states it as his opinion that the Keratosa should form 
but one family, and by the adoption of subgenera he reduces the genera 
to the following:—(i.) Ianthella. (ii.) Darwinella. (iii.) Simplicella 
(with two subgenera Aplysilla and Dendrilla). (iv.) Spongia (including 
Euspongia , Hippospongia , Cacospongla , Stelospongus , and Coscinoderma ). 
(v.) Phyllospongus (with provisional subgenera Phyllospongia and Car¬ 
ter iospongia). (vi.) Spongelia (with subgenera Pysiclea and Psammo- 
clemma), (vii.) Psammopemma (provisional), (viii.) Velaria (including 
Aplysina , Verongia , and Luffarici). 
In the body of the work the following families and genera are 
adopted:— 
Group Keratosa, Grant, 1861. Porifera with horny skeleton, devoid of 
proper spicules. 
Fam. 1. Darwinellidce , Merejowsky, 1878. Keratosa with large 
pouch-shaped flagellated chambers communicating by 
means of numerous pores in their walls with inhalent 
cavities, by means of one wide mouth with exhalent 
cavities; ground mass without granules, transparent ; 
axis of fibres thick. 
Fam. 2. Spongelidce, F. E. Schulze, 1878. Keratosa with flagellated 
chambers of more or less regularly spherical outlines, 
communication with the canal system as in the Dar- 
winellidce ; ground mass as in the Darwinellidce ; axis 
of fibre thin ; fibres cored in most cases with foreign 
enclosures. 
Fam. 3. Spong idee. Keratosa with small hemispherical flagellated 
chambers, communicating by means of numerous pores 
with inhalent, by means of special canals with exhalent, 
cavities; axis of fibre thin; ground mass about the 
flagellated chambers granulated. 
Fam. 4. Aplysinidce , Yosmaer. Keratosa with small, either hemi¬ 
spherical or pear-shaped flagellated chambers, communi¬ 
cating with exhalent and inhalent cavities, each by means 
of one comparatively long and narrow inhalent and 
exhalent canaliculus; axis of fibres thick ; ground mass 
about the flagellated chambers overloaded with gran¬ 
ules. 
Fam. Darwinellidce. 
1. Ianthella , Gray. The fibres of the skeleton contain true 
cells. 
Fam. Spong elidce. 
1. Spongelia , Nardo. With large flagellated chambers ; outer 
surface provided with conuli. 
2. Psammoclemma , Marshall. With small flagellated chambers ; 
external surface smooth. 
