62 KANSAS UNIVERSITY QUARTERLY. 



found abundantly in the Southwest. It is a large centipede, about 

 four inches long and four lines across. 



Each part of the paired testes, which lie in the dorsal region, con- 

 sists of a number of divisions. As a rule these divisions are made up 

 of two follicles, tapering toward each end, placed side by side in such 

 a way that they roughly resemble a diatom. Occasionally, however, 

 they are single ; i. e., they consist of only one follicle. The lobes are 

 connected to the vas deferens by a duct attached to one end of each 

 follicle. 



The testes which I have thus far examined are far advanced in de- 

 velopment and contain very few spermatogonia. The other genera- 

 tions of the germ-cell are, however, very well represented. 



The younger spermatocytes, with a few spermatogonia, are arranged 

 upon the periphery of the follicle, while within are the later spermato- 

 cytes and spermatids ; and, in the central portion, are large masses of 

 later spermatids and spermatozoa in various stages of formation. In 

 most of the testes examined the spermatozoa are much more numer- 

 ous than any of the other cell generations. 



In the manipulation of this material two fixing reagents were used : 

 Flemming's chrom-osmium-acetic mixture and Gilson's nitro-acetic- 

 sublimate mixture. Both of these fixatives gave excellent results, but 

 Gilson's fluid was the better. The fixation with this was perfect, there 

 being no shrinkage or other apparent distortions. 



Indeed, the only disadvantage of the Gilson fixative is the difficulty 

 experienced in the later maniixilation. When embedded in paraffin, 

 the material is so soft and spongy that it folds upon the knife in cut- 

 ting. This difficulty was obviated in the following manner : The ma- 

 terial was gradually carried up to absolute alcohol, from which it was 

 transferred to celloidin and allowed to infiltrate thoroughly. Then 

 the celloidin was allowed to evaporate gradually, until it was of the 

 consistency of thick cream. Finally all the surplus celloidin was re- 

 moved, and the mass was cleared for several hours in chloroform. 

 This accomplished, the specimen was infiltrated with paraffin and em- 

 bedded in the same substance. The material cut perfectly, without 

 any wrinkling or distortion of the sections, and without any of that 

 shrinkage of the cells which often occurs when the ordinary paraffin 

 method is employed. 



In staining, a considerable number of reagents were employed. 

 The best results were obtained with Heidenhain's iron-hsematoxylin, 

 used either alone or in connection with Congo red ; Kernschwarz ; 

 and the Flemming three-color stain. Fair results were obtained also 

 with Bismarck brown, methyl-green, cyanin, and Auerbach's methyl- 

 green and acid fuchsin. 



