176 PROCEEDIN(iS OF THK ACADEMY OF [1887. 



(3) Spongilla fragilis, Leidy. 



Syn.— 



1851 Spongilla fragilis, Ijeidy. 



1863 " lordii, Bowerhank. 



1870 " contecta, Noll. 



1878-84 " dberlea, Dybowski. 



1883 " contecta, Retzer. 



1884 " fragilis, Vejdovsky. 



1885 *' lordii, Wierzejski. 

 1885 " fragility, " 



1885 " ■ '■' Petr. 



1886 " glomerata, Noll. 



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

 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. Gemmula^ spicules numerous, straight or curved, with 

 many minute spines. Gemmulae 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 gemmulaj, according to the 

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

 forms; — the basal groups are shallow; and here the gemmulse are 

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

 consist of 2 or 3 — 30 and even more gemnuila?, forming spherical 

 or hemispherical masses. 



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

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

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

 observed in Russia, (in Donee (Donetz?) near Charkow), iu 

 Galicia, Bohemia and England and has been described repeatedly 

 by Dybowski, Retzer, ('arter, Vejdovsky, Wierztyeski and Petr. 



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

 Gemmulse generally single, surrounded by an air-chambei'-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), skeleton 

 spicules; amphidiscs smooth with entire margins, embedded at the 

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

 in Europe. 



