272 LILLIE. [VOL. I. 



be shown to be of general occurrence, it would place in a new 

 light and on a new basis the theory that the cell is composed 

 of self-perpetuating units of a lower rank. So far as these 

 observations go, they tend to confirm Watase's l theory, that 

 centrosomes and cytomicrosomes are homologous structures. 



Boveri, Brauer, 2 Van der Stricht, 3 Watase, 4 'Haecker, 5 Mc- 

 Murrich, 6 MacFarland, 7 and Klinckowstrom 8 have figured 

 structures resembling in some respects the vesicular inner 

 sphere here described. But all have designated them centro- 

 somes. Haecker, and McMurrich have not figured the true 

 centrosome at all. 



McMurrich's notice, though brief and incomplete, is of espe- 

 cial interest, because he finds that the vesicular sphere is pre- 

 ceded by a group of deeply staining granules, from which it is 

 probably derived. How, he does not know. He figures, more- 

 over, the peripheral microsomes of the inner sphere as nodes in 

 a network. From these nodes the radiating fibers arise. The 

 contents of the inner sphere ("centrosome") are "perfectly 

 homogeneous." 



MacFarland's figures are more like mine than any others in 

 the literature of the subject. Moreover, he has followed 

 through exactly the same period with which I have dealt. But 

 his conclusions are radically different, owing to his interpreta- 

 tion of the inner sphere as centrosome. With this interpre- 

 tation goes his proof of Heidenhain's " Centralspinclel und 

 Centrosomen bilden der Genese nach ein Ganzes." 



Some of Von Klinckowstrom's figures of the egg of Prosthe- 



1 Watase, S., " Homology of the Centrosome," Joitrn. of Morph., vol. viii, 

 No. 2, 1893. See also Science, 1897. 



2 Brauer, A., " Zur Kenntniss der Spermatogenese von Ascaris Megaloce- 

 phala," A rchiv f.mikr. Anat. Bd. xliii. 1893. 



3 Van der Stricht, O-, " De 1'origine de la figure achromatique de 1'ovule en 

 mitose chez la Thysanozoon brocchi," in Verh. Anat. Ges. 1894. 



4 Watase, S., " Homology of the Centrosome," Journ. of Morph., vol. viii, 

 No. 2, 1893, P- 434> figure of one of the maturation spindles of the egg of Unio. 



5 Haecker, v. ante. 



6 McMurrich, v. ante. 



7 MacFarland, v. ante. 



8 Von Klinckowstrom, A., " Beitrage zur Kenntniss der Eireifung und Befruch- 

 tung bei Prostheceraeus vittatus," Archiv f. mikr. Anat. und Entiu. Bd. xlviii, 

 Heft 4. 1897. 



