352 ' KANSAS UNIVERSITY SCIENCE BULLETIN. 



which answers were desired. Independently, the senior au- 

 thor went over the same ground, first upon material prepared 

 in this laboratory, and later upon the slides of Paulmier, Wil- 

 son and Lefevre. Whenever possible, photomicrographs were 

 made, and representations of them accompany the paper. The 

 two authors reached concordant results throughout, and their 

 common experience is embodied in what follows. 



Since the matters of dispute are purely of facts and inter- 

 pretations, it will be necessary to take a definite position on 

 each of the points involved, but so far as possible the material 

 evidence for the decisions will be presented fully. It is hoped 

 that this may be complete enough so that others interested 

 may be able to form their own opinions directly from the ap- 

 pearances themselves. There will be presented first the per- 

 sonal work of the junior author, giving her independent 

 results, and this will be followed by a general discussion of the 

 problem by the senior author. 



II. THE CHROMOSOMES DURING THE SPERMATOGENESIS OF 



ANASA TRISTIS. 



BY EDITH PINNEY. 



Preparatory to an attempted settlement of various disputed 

 questions in the development of the germ cells of Anasa tristis 

 an independent reexamination of the entire process was under- 

 taken. In order to avoid unconscious bias of opinion the pre- 

 vious reports on the spermatogenesis of this species were not 

 read. Without referring, therefore, to the accounts of other 

 observers for comparison or correlation it is purposed to record 

 the results of these observations. 



Material. — Preparation and general description. 



Material was taken from specimens of Anasa collected in 

 Lawrence, Kan., and in Woods Hole, Mass. The latter was 

 obtained through the courtesy of Dr. E. B. Wilson, of Columbia 

 University. All material was fixed in Flemming's fluid, the 

 period of fixation varying from one-half to two hours. The 

 longer fixation was found to give the better results. Paraffin 

 sections were cut five micra in thickness and stained by 

 Heidenhain's iron-hsematoxylin, Flemming's tricolor and 

 Auerbach's methods. Slides prepared by the author from 

 nineteen individuals were studied. Most of the drawings 

 were made at a magnification of 3625 diameters. This is re- 

 duced one-half in reproduction. 



