Vol. V. September, 1903. No. 



BIOLOGICAL BULLETIN. 



THE SPERMATOGENESIS OF THE MYRIAPODS. II. 



ON THE CHROMATIN IN THE SPERMATOCYTES 



OF SCOLOPENDRA HEROS. 



MAULSBY W. BLACKMAN. 



In a detailed study of the spermatocyte changes in Scolopendra 

 heros, now practically ready for publication, the multiplicity of 

 subjects requiring consideration is such that it is deemed advisable 

 to prepare a series of shorter papers, in each of which some par- 

 ticular class of structures may be considered to the practical ex- 

 clusion of the others. It is hoped that in this manner the con- 

 fusion which necessarily occurs where the whole subject is treated 

 at one time may be avoided. In this, the first of the series of 

 articles, the chromatin structures alone will be treated. 



The spermatogonia of Scolopendra are small cells of an elon- 

 gated, irregular shape lying parallel to the long axis of the follicle, 

 and containing an oval nucleus (Fig. I). During the resting 

 stages the chromatin is all aggregated into one rather large, 

 spherical nucleolus-like body, usually situated at the periphery 

 of the nucleus and apposed to its membrane. The remainder of 

 the nuclear space is filled by an irregular network of granular 

 fibers apparently differing in no way from the cytoplasmic network 

 without the nucleus. In staining reaction the nucleolar body 

 mentioned conforms in all respects to a chromatin body as it in- 

 dubitably is. When stained with Heidenhain's iron-hsematoxylin, 

 this structure retains the coloring matter after all other morpho- 

 logical elements of the cell have become almost colorless. In 

 lightly stained preparations evidences appear which warrant the 

 assertion that the body in question is not strictly homogeneous 

 in structure, but probably includes in its composition linin as 

 well as chromatin. With Flemming's three-color method the 

 " nucleolus " takes the dense red stain characteristic of closely 



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