Follicle- cells in Sal pa. 93 



the smaller blastomeres are difficult to distinguish from 

 follicle-cells, figuring and describing them as distinctly 

 difFerentj even in advanced embryos. On this point, then, 

 Salensky, Brooks, and KorotnefF agree in opposition to 

 Heider. 



As to the nature of the granular bodies in the protoplasm 

 of the blastomeres, KorotnefF says [Korotneff, iii. p. 342] : — 

 " In meiner Schrift liber die Embryologie von S. democratica 

 habe ich mich gegen die Vermuthung von Heider, wouach 

 diese Ablagerungen keine Dotterpartikelchen, sondern von 

 den Blastomeren verzehrte FoUikelzellen seien, ausgesprochen. 

 Jetzt kann ich meine Meinung bekrartigen und ganz positiv 

 behaupten, dass in den als Dotterplattcheu bezeichneten 

 Gebilden niemals eine Spur von Kernen zu sehen ist " — 

 which is certainly true, at least for S. kexagona and S.pinnata^ 

 since these granular bodies are not ingested cells, but ingested 

 follicle nuclei^ as Brooks had shown, and as is evident in the 

 material I have worked upon. The needle-like bodies figured 

 by KorotnefF in the protoplasm of tlie blastomeres of aS^. cordi- 

 formis-zonaria 1 have not seen described before. They 

 appear from his figures to be peculiarly arranged chromatin 

 particles within the ingested follicle nuclei. (Compare Korot- 

 nefF, iii. plate xiii. fig. 14.) 



KorotnefF fully confirms Brooks's description (without, 

 however, mentioning Brooks) of the disintegration of the 

 follicle-cells in the central region of the embryo, speaking of 

 a retrogressive metamorphosis of the kalymmocytes, " welche 

 ganz blass werden, sich schlecht farben, und zuletzt nur uoch 

 in Spuren zu erkennen sind. Kurz und gut, die Kalymmo- 

 cyten gehen ganz zu Grunde, und ihre Bruchstiicke dienen 

 gewiss den Histogenen [blastomeres] als Nithrmaterial " [by 

 osmosis]. (KorotnefF, iii. p. 335.) 



KorotnefF denies Brooks's statement that the organs are 

 blocked out in follicle-cells, which later are replaced by blasto- 

 mereSj saying that the organ rudiments are from the first 

 composed of blastomeres. If he is not contending over defi- 

 nitions his statements on this point are difficult to understand, 

 for his figures show with tiie greatest clearness just the con- 

 dition of attairs Brooks has described. [Compare KorotnefF, 

 iv. Taf. xviii. fig. 5 (rudiment of cloaca composed of follicle- 

 cells alone), figs. 6, 7, and 8 (rudimentary walls of amniotic 

 cavity composed wholly of ibllicle-cells), fig. 9 (pharynx 

 rudiments composed chiefly of follicle-cells) &c.] 



1 wish now to call particular attention to my own observa- 

 tions upon the nature of the disputed bodies within the proto- 

 plasm of the blastomeres of Salpa. 



