10 Spong. 
XVII. SPONGER. 
5. METHODS [cf. Titles 10, 13, 31, 39]. 
Rousseau (31) gives a general account of the methods employed in the 
study of Sponges. 
Girod (13) discusses preserving reagents for Freshwater Sponges. 
Sukatschoff (39) treats fibres of horny Sponges with eau de Javelle, 
chromic acid and gentian violet for the purpose of demonstrating their 
minute structure. 
Evans (10) describes the methods employed by him in the study of 
larvae and young fixed individuals of Spongilla. 
III. SYSTEMATIC. 
A. Recent Sponges. 
CALCAREA. 
HOMOCCELA [cf. Title 24]. 
[Nothing new.] 
HETEROCQELA [cf. Titles 6, 24, 29]. 
Sycon ciliatum and S. ramsayi redescribed, Pratt, Mem. Manchester Soc. 
xlii, No. 13. 
SI LICE A. 
TRIAXONIA. 
Hexactinellida [cf. Titles 5, 15, 34, 35]. 
Schulze, Amer. Hexact., describes the following new genera : 
Calycosoma , p. 27; 
Calycosaccus , p. 30; 
Apliorme , p. 40; 
Acanthosaccus , p. 65 ; 
Claviscopidia , p. 76 ; 
Bathyxiphus , p. 82. 
Schulze, in Amer. Hexact., describes the following new species: 
Hyalonenia schmidti , p. 6; H. hercides, p. 9; II. populiferum , p. 10; H. 
ovuliferum, p. 13; 
Holascus undulatus , p. 15; 
Calycosoma validum, p. 27; 
Calycosaccus ijimai , p. 30; 
Caidophacus agassizii, p. 36; 
Apliorme horrida , p. 40; 
Bathydorus uncifer, p. 42; 
Acanthascus plutei , p. 45 ; 
Staurocalyptus solidus , p. 51; S. fascicidatus, p. 53 ; 
Rhabdocalyptus tener , p. 57; R . nodidosus , p. 58; R. asper , p. 60; R. 
mirabilis , p. 61; 
Acanthosaccus tenuis , p. 66; 
Farrea aculeata , p. 69; F. convolvidus, p. 71; 
