Transcriber's Notes: Underscores "_" before and after a word or phrase indicate _italics_ in the original text. Small capitals have been converted to SOLID capitals. Typographical errors have been silently corrected but other variations in spelling and punctuation remain unaltered. The quotations in German appear to have some errors, but these quotations have been reproduced exactly as in the original paper. THE KANSAS UNIVERSITY SCIENCE BULLETIN. (VOL. I, NO. 2—FEBRUARY, 1902. Whole Series, Vol. XI, No. 2.) CONTENTS: SPERMATID TRANSFORMATIONS IN GRYLLUS ASSIMILIS, WITH SPECIAL REFERENCE TO THE NEBENKERN. —_W. J. Baumgartner._ PUBLISHED BY THE UNIVERSITY, LAWRENCE, KAN. Price of this number, 30 cents. Entered at the post-office in Lawrence as second-class matter. KANSAS UNIVERSITY SCIENCE BULLETIN. VOL. I, NO. 2. FEBRUARY, 1902. {WHOLE SERIES, {VOL. XI, NO. 2. 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 spermatid 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 findings, 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 impossible, to secure good, clear results; at least, neither Gilson’s nor Zenker’s mixture did any better on cells in these stages. Heidenhain’s iron-hæmatoxylin stain gave the best results, although Flemming’s three-color method was very satisfactory.