Kansas University Science Bulletin. 



Vol. I, No. 2. FEBRUARY, 1902. I^o^i 8 ™- 



SPERMATID TRANSFORMATIONS 

 In Gryllus assimilis, with Special Reference to the Nebenkern. 



( Thesis for the degree of Master of Arts.) 



BY W. J. BAUMGARTNER. 

 With Plates II and III. 



I.— Methods. 

 II.— Material. 

 III.— Observations. 



(a) Nucleus. 



(b) Cytoplasmic Structures. 



1. Nebenkern. 



2. Acrosome. 



3. Axial Filament. 



4. Centrosome. 



5. Cell Body. 



(c) The Spermatozoon. 

 IV.— Comparison of Results. 



V.— Summary. 



IT is the object of these studies to follow carefully the sperma- 

 tid transformations, and, if possible, to get a complete series 

 of changes occurring therein. I do not pretend that I have as 

 yet found all the stages, but in the present paper will publish 

 observations made on Gryllus assimilis pertaining chiefly to the 

 nebenkern, of which I have found some stages not previously 

 described, as far as I know. I shall first describe my own find- 

 ings, and then compare them with the results of others. 



I. Methods. 



While other fixing agents were used, Flemming's chromo- 

 acetic-osmic mixture (strong) proved the best. Its fixation was 

 satisfactory in all but a few stages, where the chemical changes 

 going on in the cell are such that it seems difficult, probably im- 



(47) 



