402 MONTGOMERY. [Vol. XV. 



lin, indigo-borax carmine (Norris and Shakespere), and certain 

 others were tried, but proved unsatisfactory. With the excep- 

 tion of the three triple stains mentioned, the others were used 

 in various combinations as double stains ; worthy of recommen- 

 dation are (with especial regard to the differentiation of the nucle- 

 olus) Delafield's, or better, Ehrlich's haematoxylin followed by 

 eosin ; acid carmine followed by nigrosine ; methylen blue fol- 

 lowed by brasilin. Other combinations were also used, but it is 

 not necessary to mention these here, nor to speak of the dura- 

 tion of the staining baths, since in the explanation of the figures 

 these data are given for each case separately. 



For the study of the finer structural details, the yVth homo- 

 geneous immersion lens of Zeiss was used, in combination with 

 oculars 2 and 4. I would emphasize the fact that the drawings 

 from the preparations were made gradually, as I proceeded in 

 the study of each particular cell, and were not postponed until 

 the end of the particular investigation, so that almost all were 

 made before I had arrived at any views upon the nature of the 

 nucleolus ; and I have pursued this method in order to elimi- 

 nate from the figures as much as possible of the subjective ele- 

 ment. In other words, I have made as close copies as possible 

 of the preparations, drawing every cell or structure present- 

 ing some appearance with which I had not as yet become 

 acquainted, or rather the significance of which I had not 

 learned, and then from the figures so made I have endeavored to 

 learn the nature of the phenomena there presented, at the 

 same time recurring to the preparations themselves. This 

 method of study is the one employed by many investigators, 

 though it can scarcely be termed the one most in vogue. The 

 colors of the original figures have on the whole been most excel- 

 lently reproduced by the lithographs of Werner and Winter. 



B. Protozoa. 



I. Gregarhte from Lineus gesserensis (O. F. Miill). 

 (Plate 21, Figs. 1-19.) 



{Description of the animal. — The largest individuals are just 

 visible to the naked eye, and are of a whitish color. No 

 synzigia were observed among the thirty individuals exam- 



