60 Dr. W. Dybowski on the 



Dosilia (?) Stepanoivu, n. sp. 



This Spongilla, from Lake Wielikoje, is of very peculiar 

 interest. So far as I know, no form similar to our sponge 

 has hitherto been described among the European Spongillidae, 

 at least, I have been unable to find any notice of it in the 

 literature accessible to me ; on the other hand, among the 

 exotic (American and Asiatic) Spongillidse, I find analogous, 

 and, it seems to me, nearly allied forms. 



The genus DosiHa, Gray*, which Carter f places in his 

 " Meyenia,^^ possesses two species — Dosilia plumosa (from 

 Bombay) and D. Baileyi (from New York). The latter 

 appears to me the form most nearly allied to our sponge J. 



To justify and support my opinion I will here give as 

 accurate a description as possible of our sponge, and then 

 place side by side the most prominent characters of the two 

 (Kussian and American) sponges, so as to facilitate for other 

 authors the comparison of the two sponges with one another. 



Description. — Of the sponge under consideration I have 

 before me six small spirit-specimens, all ol which are defec- 

 tive and do not enable us to form any definite notion of their 

 form. They are chiefly shapeless masses, growing round 

 various foreign bodies (such as leaves and stalks of grasses, 

 fragments of bast, very thin twigs, and even quills of a small 

 wing-feather). The specimens in spirit are pale tawny, and 

 look not unlike soaked bread. The skeleton-spicules are long 

 and slender acerates with acute ends, that is to say, they have 

 the form of the spicules proper to the Spongillge with smooth 

 spicules in general ; but they are somewhat smaller, their 

 length being 0-200-0-104, and their thickness 0-065-0-004 

 millim. The surface of the skeleton-spicules is, however, 

 not smooth, but furnished with very short, acute, and exceed- 

 ingly scattered spines §. 



* J. E. Gray, " Notes on llie Arrangement of Sponges, Avith the De- 

 scription of some new Genera," in Proc. Zool. Soc. Loncl. 18G7, pp. 550- 

 553, pis. xxvii. & xxviii. 



t Carter, " Historj- and Classification of the known Species of Sjmn- 

 gilla," in Ann. &- Mag. Nat. Hist. ser. 5, vol. vii. (1881), pp. 78-107, 

 pis. V. & vi. 



\ Neither of the two species mentioned is known to me by autopsy. I 

 have draAvii my conclusions as to the affinities of our sponge only from 

 the statements in the literature, and must therefore for the present abstain 

 from a certain and final decision. 



§ The above-mentioned spines are so small and inconspicuous that 

 they may very easily be overlooked. They are most conveniently observed 

 with the light of an oil-lamp and with the objective no. 8. When they 

 have once been observed they may quite easily be recognized with objec- 

 tive no. 4. The spines appear most distinctly at the periphery of the 

 spicules. 



