M CLUNG : SPERMATOCYTE DIVISIONS OF THE ACRIDID.E. 75 



and Flemming. Gilson's aceto-nitric-sublimate fluid, liowever. gave 

 very satisfactory results. 



For staining, Heidenhain's iron-luvniatoxylin method was largely 

 and most satisfactorily employed. This was supplemented by the use 

 of Flemming's triple stain, which is very valuable for indicating the 

 chemical condition of the cellular elements during division. 



II. — NOMENCLATURE. 



In order to avoid misunderstandings concerning the different steps 

 in the process of spermatogenesis, I will briefly outline the nomencla- 

 ture that I employ. This, as will be observed, is the one proposed by 

 la Valette St. George. According to it, the cells arising from the pri- 

 mordial germ cells are designated as spermatogonia up to the time 

 when they cease dividing for a period and undergo a considerable in- 

 crease in size. The exact period at which the cells of this generation 

 pass over into the next is marked by the reconstruction of the 

 daughter cells of the last division, during which the spermatogonia! 

 chromosomes are diffused into material for the formation of the .sper- 

 matocyte spireme. 



This is a clearly indicated change in the material that I have 

 studied, for the following reasons: (1) There is a marked difference 

 in the staining reaction of the spermatogonia and that of the other 

 cell generations, both in the resting condition and during division. 

 This consists in a stronger general affinity for the coloring matters as 

 manifested by all the cell elements, so that the region ot" the testis 

 occupied by these cells presents a deeper coloration than other por- 

 tions. (2) The cells, because of the rapidity with which they divide, 

 are smaller than those of the succeeding cell generations, and the 

 nuclei occupy a relatively larger area. (3) The number of chromo- 

 somes* is the same as that of the body cells, and during division the 

 elements are rod-shaped and split in elongated halves. (4) The 

 spindle is shorter and its outline broader than that of the spermato- 

 cyte division figures. (5) The centrosomes are often more clearly 

 distinguishable during the spermatogonia! division than they are in 

 later ones. 



Immediately after the last spermatogonial division the cells cease 

 to divide, and, during a considerable length of time, merely increase 

 in size. These cells are the spermatocytes. In Hippiscus, the cells 

 of the testis pass through the winter in the pi'cjphases of this stage. 

 Early in the spring they commence to divide vigorously, and in the 

 division figures the number of chromosomes is but half that of the 

 spermatogonia. The spermatocytes which have quadripartite chronio- 



*The material derived from irii>))i.ic'ix is not suited to the determination of numerical ratios, 

 owing to the large size and loose distribution of the elements. I therefore accept the authority 

 of other investigators, pending the search for a favorable object. 



