380 The Unity of the Organism 



capsule. A. Borgert, in particular, has recently investi- 

 gated this subject. These openings, known as astropyles, 

 as^p, figure 25, a, b, c, and parapyles, are characteristic 

 organs of many Radiolaria. They are the communications 

 between the body substances situated inside and outside of 

 the central capsule. Borgert had shown in an earlier paper 

 that when fission of the animal takes place new parapyles 

 arise de novo, and not by division of the original organs. 



In the memoir now before us he confirms his former obser- 

 vation on the origin of the parapyles and shows that new 

 astropyles arise by division of tlie old. The chief interest 

 for us in this later study lies in observations on the relation 

 of the development of the organs to the behavior of the 

 nucleus. Besides the indirect or mitotic mode of division 

 of the nucleus proviously studied, Borgert now describes two 

 other modes, one of which is a peculiarly modified indirect 

 division, and the other a quite unique performance which he 

 characterizes as "ruffle-like" (Manschettenforni).^ Into the 

 details of these modes of division we need not go. Sufficient 

 for us is it to point out that the great nuclear mass n. fig- 

 ure 25, consisting of a veritable throng (a thousand or 

 more) of chromosomes, retains its massed character through 

 all the division stages. The author lays special emphasis on 

 the facts that at no time does the nuclear membrane dis- 

 appear; and that the endoplasm within which the nucleus 

 is embedded takes no "active part in the process of di- 

 vision," nor does it undergo "any sort of special structural 

 change." The division of the astropyle and the origin of 

 new parapyles are correlated in time with the nuclear divi- 

 sion; but even this correlation is incomplete. Interestingly 

 enough, the formation of new parapyles is far advanced, 

 the author says, "when the condition of the nucleus indicates 

 the first beginning of the process of division." And Borgert 

 remarks : "It appears therefore that the foundation of the 

 new structure results before the beginning of nuclear di- 



