14 THOS. H. MONTGOMERY jr., 



ject of much study but more conjecture in the male sexual elements, 

 namely the so-called "attraction sphere". Now as has been pointed 

 out by V. Erlanger ('96 b, '97 a, b) with correctness , "attraction 

 sphere" was the term introduced by Van Beneden ('83) to denote the 

 central portion of the astral figure in Ascaris^ i. e. to denote an 

 integral portion of the spindle. Boveri's term "archoplasm" though 

 applied to approximately the same structure does not respresent the 

 same idea, since he supposes this "archoplasm" to be a chemi- 

 cally specific cytoplasmic substance (equalling the "kinoplasra" of 

 Strasburger) which is the only portion of the cytoplasm, according 

 to BovERi, which forms the rays of the spindle. It would be out of 

 place here to enter into the discussion as to whether an "archoplasm" 

 really occurs in the sense intended by Boveri. What is to the point, 

 however, is that the substance of the so-called "attraction sphere" of 

 the male sexual cells, as far as has been accurately determined, and 

 as will be shown here for the case of Pentatoma, takes no part in 

 the formation of the spindle fibres, and hence v. Erlanger was quite 

 justified in concluding that this body can be identified with neither 

 the true attraction sphere nor with the hypothetical archoplasm. This 

 body of the male elements also cannot be homologized with the Neben- 

 kern, though this term is frequently applied to it, since Nebenkern 

 was first applied by Bütschli to a structure in spermatids derived 

 from the connective fibres of the spindle. Accordingly, v. Erlanger 

 suggests for the body in question the term "Centrodeutoplasma". 

 Meves ('97) however, on the ground that this term suggests that this 

 substance is made up in part of yolk (deutoplasma), proposes for it 

 the name "Idiozom", which I shall adopt in the present paper. But 

 I am not ready to go so far as he does, including under this 

 term also the so- celled "Dotterkerne" ("yolk nuclei") of ovarial eggs, 

 since it is possible that under the latter name are grouped together 

 heterogeneous structures, as e. g. some of the yolk nuclei have sub- 

 sequently been determined to be nothing more than the first stages 

 of yolk. 



In the idiozome of the resting spermatogonium I have been 

 unable to detect any granules which could be regarded as centro- 

 somes, though such might possibly be demonstrated by the iron 

 haematoxyline stain. 



The nucleus of the resting spermatogonium is comparatively large 

 and is situated at the larger end of the cell. In it the chromatin is 

 arranged along the linin network in the form of microsomes (Figs. 1 — 4), 



