1887.] NATURAL SCIENCES OF PHILADELPHIA. 271 



(2) Lubomirskia bacillifera, Dybowski. 



Sponge "massive, more or less lobed. Structure much the same 

 as that of the foregoing species, but finer and softer. Color grass- 

 green. Skeleton spicule curved, cylindrical, sometimes fusiform, 

 round at the ends, and spiniferous generally, but more particularly 

 over the ends ; sometimes smooth over the rest or middle of the 

 shaft. Parenchyma spicule a small, thin, smooth acerate." Carter. 



Loc. Lake Baikal. 



(3) Lubomirskia intermedia, Dybowski. 



Sponge "flat, spreading. Structure like that of X. baicalensis, but 

 more tender. Color yellowish or olive-green. Skeleton-spicule 

 curved, fusiform, gradually sharp-pointed, spiniferous generally. 

 Parenchyma spicule a large, smooth acerate." Carter. 



Loc. Lake Baikal. 

 (4j Lubomirskia papyracea, Dybowski. 



Sponge "papyraceous in thinness, with "smooth, shining surface. 

 Structure very soft. Color white. Skeleton thick, (seven times 

 longer than broad), curved, cylindrical, round at the ends, thickly 

 spiniferous throughout. Parenchyma spicule a very small, smooth 

 acerate." Carter. 



The above species, described by Dr. W. Dybowski, were collected 

 by his brother Dr. Benedict Dybowski and Herr W. Godleuski, all 

 from Lake Baikal in Siberia. Very many specimens were obtained 

 by them from various depths in the Lake, and the conclusion reach- 

 ed by their intelligent observations was that the sponge was totally 

 devoid of gem mules. I do not know that these observations suffi- 

 ciently covered the range of the seasons, to make the result positive. 

 The condition of Lake Baikal as a geologically "recent" fresh-water 

 lake, still retaining in its fauna etc., traces of its former marine 

 character, (such as the existence of seals in it or in a recently con- 

 nected body of water), renders these observations peculiarly import- 

 ant. 



