No. 3.] THE PROTOZOA AND METAZOA. 729 



It appears, therefore, that the archoplasm-theory in its 

 original form is far from being definitely established. Heiden- 

 hain ('94, '97), one of the chief opponents of the archoplasm 

 idea, has, however, described a substance connected with the 

 centrosome which is of considerable interest in relation to 

 that theory. In resting cells this substance is described as 

 follows : " Diese Centralkorper sind innerhalb des Microcen- 

 trums durch eine Zwischenmasse miteinander verbunden, 

 welche meist recht gut sichtbar ist, und im giinstigen Fall 

 durch das Rubin der Praparate stark gefarbt erscheint. Diese 

 Zwischenmasse entspricht ganz genau der Materie der ' pri- 

 maren Centrodesmose ' beim Leukocyten " ('97, p. 231). It is 

 composed of minute granules, and from it are developed the 

 fibers of the central-spindle which form the secondary " Centro- 

 desmus." This substance would seem to agree to a certain 

 extent with the " archoplasm " of Boveri's theory, and I believe 

 that it may be compared to the substance of the sphere in 

 Noctiliica. Like the centrodesmus, the sphere is made up of 

 granules surrounding the centrosome, and during mitosis the 

 central-spindle fibers are formed from it. Like archoplasm, 

 it is a specific substance in the cell, surrounding the centro- 

 some and giving rise to the spindle-fibers. While Boveri's 

 original conception of archoplasm as a distinct substance in 

 the cell may not hold for the Metazoa, it is, I believe, entirely 

 consistent with the facts in Protozoa, as will be shown in the 

 comparative part of this paper.^ 



4. The Mantle-fibers. 



It has been shown above that the fibers of the central-spindle 

 have no connection with the chromosomes, but pass without 

 interruption from pole to pole. In the metaphase, and after 

 the disappearance of the membrane, a second set of spindle- 

 fibers is formed, passing from the sphere to the ends of the 

 chromosomes. These are the mantle-fibers or " radial-fibers " 

 of Ishikawa. He speaks of them as follows: "Of the origin 

 of the mantle-fibers in Noctiliica, I can say but a few words, 



1 Cf. p. 755. 



