196 MAULSBY W. BLACKMAN. 



Upon higher magnification, sections of this karyosphere usually 

 present a granular or spongy appearance as shown in Fig. 9, c. 

 In other cases the chromatin is more or less collected into cer- 

 tain areas forming a coarse cluster in the center from which proc- 

 esses extend toward the periphery (Fig. 9, $). Here the body 

 still retains its approximately spherical form, the portion between 

 the processes not staining with the chromatin stains but showing 

 the plasma reaction. Quite often, al?o, we find a karyosphere 

 which presents the appearance shown in Fig. 9, c. This I regard 

 as the typical form. It consists of very fine and closely aggre- 

 gated mass of chromatin filaments arranged in the form of a 

 more or less perfect sphere. Upon one side of this mass when 

 the section is cut through the right plane is a smaller homo- 

 geneous body, the accessory chromosome (Fig. 9, d, e). The 

 remainder of the karyosphere is made up of irregularly arranged 

 chromatic strands between which minute interstices, undoubtedly 

 filled with karyolymph, may be discovered by careful focusing. 



Thus it will be seen that during the pseudo-germinal vesicle 

 stage, 1 the karyosphere, with the exception of a membrane, pos- 

 sesses all of the essential elements of a nucleus chromatin, 

 linin (upon which the chromatin is arranged) and karyolymph. 

 It is in fact a "nucleus within a nucleus" similar to that de- 

 scribed by Carnoy in the closely allied genera of chtlopods, 

 LitJiobins, Scutigcra and Geopliiliis. This structure which he 

 calls the " nucleole noyau," behaves similarly in all essential re- 

 spects during the first spermatocyte to the karyosphere in Scolo- 

 paidra licros? It is derived from the chromatin of the nucleus 

 in a similar manner and during the first maturation mitosis be- 

 haves in a way essentially alike in all respects. 



Carnoy by no means stands alone in the assertion that func- 

 tional chromatin may and does assume the form of nucleolus- 

 like bodies during resting periods between mitoses, although the 

 structures found by him in LitJwbins, Scutigcra, etc., are more 

 highly organized than those reported by others. Among those 

 who have observed that the "chromatin nucleolus " is derived 



1 See former paper. 



2 Carnoy failed to find a ' ' nucleole noyau " in S. dalmatica. He considers the intra- 

 nuclear body in the cells of this animal a true plasmasome in no way related to the 

 structure found in Lithobius and other chilopods. 



