414 Miscellaneous. 



possibility of briefly communicating the results at which I have 

 arrived during my investigation of this question. 



1. The appearance of the glistening granules (yolk-substance) 

 in the ordinary amoeboid cells must be regarded as the earliest 

 stage in the development of the gemmules. 



2. These cells with the glistening granules (" trophophores " 

 of Marshall *) begin to glide towards oue another, while they are 

 joined by a fairly large number of ordinary parenchyma cells. 



3. Notwithstanding the assertions of Goette t, neither the ciliated 

 chambers nor the canals take part in the development of the 

 gemmules. 



4. The cells which have glided together unite, and form a small 

 spherical lump, the central mass of the future gemmule, around 

 which the parenchyma cells group themselves in several concentric 

 rows. 



5. The number of the glistening granules in the cells of the 

 central mass increases visibly, so that the ordinary parenchyma 

 cells which were at first observed between those cells completely 

 disappear. 



6. The peripheral cells of the parenchyma, which group them- 

 selves concentrically around the central mass, gradually assume a 

 clavate form and arrange themselves radiall}', as was perfectly 

 correctly described by Goette. 



7. Moreover these cells group themselves into one, and not into 

 from two to three laj'ers, as Goette maintains, and that, too, not 

 simultaneously over the entire surface of the future gemmule. 



8. The lower expanded disciform ends of the clavate cells secrete 

 a chitinoid cuticle, the first internal layer of the future shell of the 

 gemmule, as is quite correctly stated by Goette. 



9. There is no " enveloppe primitive" around the central mass of 

 the future gemmule, as described by Wierzejski J. 



10. Amphidiscs are not formed in the clavate ceUs of the shell of 

 the gemmules, as is described and figured by Goette §. 



11. The amphidiscs appear outside these cells, exactly as described 

 by Wierzejski ; and moreover they group themselves in concentric 

 zones aroimd the clavate cells. 



12. I have succeeded in observing amphidiscs from the earliest 

 stages of their development until they were fully formed, and I 

 always found them outside the clavate cells. 



* W. Marshall, " Vorliiufige Bemerkungen liber die Fortpflanzimgsver- 

 haltnisse vou Spongilla lacustrisf Sitzungsbeiicbte der naturforsch. 

 Gesellschaft zu Leipzig, 1884. 



t A. Gcette, ' Untersuchungen zur Entwicklungsgescliichte von Spon- 

 ffillajluviatilis,' 1886. 



X A. Wierzejski, " Le d^veloppement des gemmules des eponges d'eau 

 douce d'Europe," Archives slaves de Biologie, t. i. 1886, f. 8. 



§ Loc. cit. Taf. V. figs. 35 & 36. 



