213 



Heider's account of the embryology of Salpa fusiformis, pub- 

 lished in 1895, differs in certain points from preceeding accounts. 



He interprets the granular bodies in the protoplasm of the blasto- 

 meres as ingested follicle cells and figures them as containing 

 nuclei (Plate I, Figs. 4, 10^, 10^), and largely from this observation 

 argues, as Brooks had shown, that the follicle cells serve as food for 

 the blastomeres. 



Heider places emphasis upon the unequal cleavage of the Salpa 

 ovum, claiming, contrary to Salensky and Brooks, that, except in 

 the early stages, the micromeres can not be distinguished from the 

 follicle cells, and that organ rudiments which are apparently formed 

 from follicle cells are really composed of small blastomeres. 



The insufficient reference in Heider's paper to Brooks' Mono- 

 graph may perhaps be explained by the fact that Heider's paper was 

 practically complete before Brooks' work was published. 



Korotneff's several papers are the most recent dealing with 

 this subject. This author denies Heider's contention that the smaller 

 blastomeres are difficult to distinguish from follicle cells, figuring and 

 describing them as distinctly different, 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 IH. page 342]: »In meiner 

 Schrift über die Embryologie von aS*. democratica habe ich mich gegen 

 die Vermuthung von Heider, wonach diese Ablagerungen keine 

 Dotterpartikelchen, sondern von den Blastomeren verzehrte Follikel- 

 zellen seien, ausgesprochen. Jetzt kann ich meine Meinung bekräf- 

 tigen und ganz positiv behaupten, daß in den als Dotterplättchen 

 bezeichneten Gebilden niemals eine Spur von Kernen zu sehen ist(f, 

 which is certainly true, at least for *S'. hexagona and S. pmnata, 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 Avorked upon. The needle-like bodies figured by Korotneff in 

 the protoplasm of the blastomeres of *S'. cordiformis-zonaria I have not 

 seen described before. They appear from his figures to be peculiarly 

 arranged chromatin particles within the ingested follicle nuclei. (Com- 

 pare Korotneff HI. Plate B, Fig. 14.) 



Korotneff fully confirms Brooks' description (without however 

 mentioning Brooks) of the disintegration of the follicle cells in the 

 central region of the embryo, speaking of a retrogressive metamor- 

 phosis of the Kalymmocytes, «welche ganz blaß werden, sich schlecht 

 färben und zuletzt nur noch in Spuren zu erkennen sind. Kurz und 



