214 



gut, die Kalymmocyten gehen ganz zu Grunde, und ihre Bruchstücke 

 dienen gewiß den Histogenen [Elastomeres] als Nährmaterial« [by os- 

 mosis]. (Korotneff III. page 335). 



Korotneff denies Brooks' statement that the organs are blocked 

 out in follicle cells which later are replaced by blastomeres, saying 

 that the organ rudiments are from the first composed of blastomeres. 

 If he is not contending over definitions, his statements on this point 



Portion of a section of a young embryo of Salpa hexagona showing one blasto- 

 mere and fifteen migrated follicle cells. Bl, blastomere; N, nucleus of blastomere; 

 <i, b, c, d, e,f, g, h,j, k, nuclei of follicle cells ingested by the blastomere. 



Leitz 1/12 objective, no. 8. compensating ocular. 



are difficult to understand, for his figures show with the greatest clear- 

 ness just the condition of affairs Brooks has described [Compare 

 Korotneff IV. Taf XVIII. Fig. 5 (rudiment of cloaca composed of 

 follicle cells alone), Fig. 6. 7 and 8 (rudimentary walls of amnionic 

 cavity composed wholly of follicle cells). Fig. 9 (pharynx rudiments 

 composed chiefly of follicle cells) etc.]. 



I wish now to call particular attention to my own abservations 



