SILICIOUS AND HORNY SPONGES WILSON. 479 



subdivisions owing to the occurrence of intermediates, it comes to 

 be a question as to what method of notation we shall employ in the 

 designation of individuals. Perhaps we shall have to limit ourselves 

 to the erection of a certain number of standard combinations (varie- 

 ties or subspecies) and designate nonconforming individuals as near 

 certain of these standard forms. 



With regard to the fascicled character of the main fibers in 

 Spongelia. it may be called to mind that Hyatt (1877, p. 545) states 

 that in the specimens which he refers to Dysidea fragilis Johnston 

 the primary fibers are often compound. Schulze (1879 &, p. 124) 

 refers to this fact, and further on (p. 151) in the same memoir de- 

 scribes fascicular main fibers in S. elegans Nardo. In S. fragilis, v&r. 

 implexa, from Australian waters, Lendenfeld (1889, p. 666) says 

 " exceptionally a fascicular structure is indicated in the areniferous 

 main fibers, 0.17-0.2 mm. thick." Wilson records (1902, p. 410) 

 that in the Porto Eican sponge referred to S. paUesccus fragilis. var. 

 ramosa, the main fibers are somewhat fascicular. 



Since Lendenfeld's monograph (1889), where the distribution is 

 given, the species has been taken several times. Topsent lists it for 

 the Azores (1892) and again for Amboina (1897). Dendy (1905) 

 refers Ceylon sponges to it, splitting the species after Lendenfeld 

 into S. fragilis and S. elastica. Hentschel (1921) lists two varieties 

 from the Aru Islands. Stephens (1912, 1917) records the species 

 from the Irish coast. Dendy (1916 b) records it from Okhamandal 

 and questions (p. 139) the desirability of separating S. elastica from 

 S. fragilis. It would seem that the species name is used by all these 

 authors in the limited sense of Lendenfeld's monograph. 



Family SPONGIDAE. 



Spongidae Lendenfeld, 1889, p. 121. 



Sponges with small flagellated chambers, 20 to 50 \i wide, and a 

 skeleton, generally in the shape of a reticulum, composed of solid, 

 or pithed, horny fibers. In exceptional cases the whole fiber may 

 consist of pith-substance. 



Subfamily Eusponginae. 



Eusponffmae Lendenfeld, 1889, p. 123. 



Skeletal reticulum close-meshed, the fibers solid, containing only 

 a narrow medullary streak instead of a conspicuous pith as in the 

 Aplysininae. Main and connective fibers generally distinguishable; 

 all fibers simple, none fascicular. Main fibers usually with foreign 

 bodies, which are. however, in general small, not distending the fiber. 



