378 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Porifera. 
Gemmules of Ephydatia.* — Herr W. Zykoff has investigated the 
development of the gemmules of Ephydatia fluviatilis. The first hint 
of their development is the appearance of refractive (yolk) granules 
in the amoeboid cells ; these cells (Trophophores of Marshall) combine 
in company with ordinary parenchymatous cells ; neither ciliated 
chambers nor canals have any part in the making of the gemmules ; 
the trophophores unite in a central clump around which the paren- 
chymatous cells are ranged concentrically ; the number of granules in 
the cells of the central mass increases, and ordinary parenchymatous 
cells which have been included disappear ; the peripheral paren- 
chymatous cells become club-shaped and radially grouped, as Goette 
has described ; they form only one layer ; the low T er, disc-like ends of 
the club-shapel cells secrete a chitinous cuticle — the first sheath of 
the future shell of the gemmule ; there is no “ enveloppe primitive,” 
such as Wierzejski has described, around the central mass; the amphi- 
discs are not formed, as Goette described, in the club-shaped cells, but 
outside of them, as Wierzejski stated ; they become grouped in con- 
centric zones round the club-shaped cells, but penetrate gradually into 
the cellular layer and are distributed within it ; the cells pressed out 
by the amphidiscs form externally a second chitinous cuticle ; they 
atrophy as the gemmule is completed. It is on physiological grounds 
unlikely that the same cells could form both chi tin and siliceous amphi- 
discs. 
Rare European Spongillidse.t — Dr. A. Wierzejski records his dis- 
covery in Galicia of the rare Spongillid Carterius Stepanovii Petr. 
( Dossila Stepanovii Dyb.) which has only been found three times in 
Europe, and of the North American Heteromeyenia repens Potts, for the 
first time found in Europe. 
Homodermidae.J — Dr. R. v. Lendenfeld replies to Bidder’s criticism 
of his two families Homodermidas and Leucopsidm, maintaining that 
they are thoroughly justifiable. The family Homodermidas depends not 
solely on Homoderma, though Lendenfeld adheres to his description of 
that genus, but also on other forms, one of which the author has recently 
described as Homandra falcata. 
Sponges of the Adriatic.! — Dr. R. v. Lendenfeld has commenced a 
monographic account of the Sponges of the Adriatic, as it is now nearly 
thirty years since the late Oscar Schmidt published his well-known 
work. He gives full descriptive accounts of thirty-two species, all 
belonging to the Calcispongife. 
Study of Clionidae.il — M. E. Topsent gives a monographic review 
of the genera Cliona, Tlioosa, and Alectona, the later of which are dis- 
tinguished from the first by having their principal microscleres amphi- 
asters and not spirasters. He places them among the Clavulidse, of 
which they are the perforating forms. The perforating genus Saurus 
of Gray is regarded as a true Tetractinellid, and not as a Clionid. 
* Zool. Anzeig., xv. (1892) pp. 95-6. 
+ Biol. Centralbl., xii. (1892) pp. 142-5. J Zool. Anzeig., xv. (1892) p. 109. 
§ Zeitsehr. f. Wise. Zool., lii. (1891) pp. 185-821 (8 pis.). 
|| Arch. Zool. Expe'r. et Gc'u., ix. (1891) pp 555-92 (1 pi.). 
