Dr. M. Dybowski on Dosilia Stepanowii. 253 



lamella, 0*036 millira. broad, which forms the pore-appen- 

 dage. At its four corners the lamella is produced into tags 

 {Zipfel) . These tags, from three to five in number, are not only 

 of different length and thickness, but also variable in form. 

 In some specimens they all terminate acutely and are cither 

 simple or bifid at the end ; in others, on the contrary, they are 

 curved into a sickle-shape at the ends. 



Among the numerous preparations examined I have met 

 with only two gemmules in which the pore possessed no 

 appendage and in which the walls of the pore were entirely 

 uninjured. 



The pore-appendage has hitherto been observed only in 

 the American species *. The sponge now under considera- 

 tion is therefore the first European iSpongilla in which this 

 organ has been observed. 



The pore-appendage is evidently locomotory in its signi- 

 ficance. How very differently constructed the apparatus 

 serving for locomotion may be has been shown by H. J. 

 Carter {loc.cit.). We also find a very peculiar locomotory 

 arrangement in Trocliospongiiia erinaceus, Ehrenberg, Avhich 

 has been recently discovered and described by Prof. Vej- 

 dovsky f. 



Yejdovsky regards the cell-structure and even the pore in 

 Sj^ongilla sihiVica, milii, as an analogous locomotory arrange- 

 ment. Evidence in favour of this assertion will shortly be 

 published. 



5. The Germinal Matter (Vejdovsky's " Kelmkorper "). 



The gemmule is completely filled with a cellular substance. 

 This substance can be observed in its natural form and con- 

 dition only in quite fresh sponges, otherwise it appears in a 

 somewhat altered state. 



If we prepare a transverse section of the gemmule from a 

 dried or spirit specimen, we find that its whole cavity is filled 

 with numerous round or elliptical corpuscles. The largest 

 of these corpuscles hardly attain 0'002 millim. in diameter ; 

 they are usually smaller, and sometimes even too small to be 

 measured. All these corpuscles are loosely scattered, and 

 always occupy the whole field. The coi-puscles are distinctly 

 contoured, but show no distinctly limited nucleus, although 



* See H. J. Carter, " On Sj)07iffiophora Pottsi" in Ann. & Maf?. Nat, 

 Hist. November 1881 ; and " Form and Nature of the Cm'ous Appen- 

 dages on the Statoblasts, &c.," ibid. May 1882. 



t F. Vejdovsky, ' Piispevky k znamostem o houbach sladkovoduich,' 

 Praha, 1883, figs. 3-6 ; H. J. Carter, Ann. & Mag. Nat. Hist. February 

 1884:, pi. vi. figs. 3-6. 



