176 PROCEEDINGS OF THE ACADEMY OF [1887. 



(S) Spongilla fragilis, Leidy. 



Syn.- 



1851 Spongilla fragilis, lue'idy. 



1863 " lordli, Bowerbauk. 



1870 " conteda, l^oW. 



1878-84 " dberica, Dybowski. 



1883 " conteda, Retzer. 



1884 " fragilis, Vejdovsky. 



1885 " lordii, Wierzejski. 

 1885 " fragilis, 



1885 " '' Petr. 



1886 " glomerata, Noll. 



Colony not branched ; pale or brown in color, with large osculae 

 which, as a rule, are grouped in large cavities of the surface. Pores 

 numerous and small. Skeleton spicules, nearly straight or but 

 slightly bent; sharp-pointed, smooth, not rarely thickened in the 

 middle. Gemmulae spicules numerous, straight or curved, with 

 many minute spines. Gemmul?e small, spherical, with a high, 

 generally horn-shaped, polar tube, which is filled with air and 

 projects from the air-chamber-layer; the latter consists of large, 

 radial rows of cells. The groups of gemmulse, according to the 

 species (?) and the place of developnient, present two principal 

 forms; the basal groups are shallow; and here the gemmulje are 

 placed pavement-like, close together; tliose formed in the parenchyma 

 consist of 2 or 3 30 and even more gemmuloe, forming spherical 

 or hemispherical masses. 



This species, 8. fragilis, first described by Leidy, in America, 

 was later described in Siberia by Dr. Ben. Dybowski, and finally 

 by Noll, as S. conteda (and S. glomerata). Recently it has been 

 observed in Russio., (in Donee (Douetz?) near Charkow), in 

 Galicia, Bohenna and England and ha^s been described repeatedly 

 by Dybowski, Retzer, Carter, Vejdovsky, Wierzejeski and Petr. 



(B) Sub-Family, MEYENIN^, Carter. 

 Gemmulae generally single, surrounded by an air-chand)er-layer 

 in which amphidiscs are embedded in one or moie series, one above 

 another. They are either star-shaped or have entire margins. 



(II) Gen. TROCHOSPONGILLA, Vejdovsky. 

 With smooth, (T. leidyi), or rough, (T. erenaceus), skeletosn 

 spicules; amphidiscs smooth with entire margins, embedded at the 

 base of an air-chambex--layer. Only one species has been found 

 in Europe. 



