138 J- Moore, 



which have convinced me that this centering of the fibres about an 

 intermediate body is the exception rather than the rule. The existence 

 or non-existence of the body named, however, in no way affects the 

 view I put forward, that the Nebenkern (archoplasm) of the salamander 

 is derived, as it undoubtedly is, from a partial or complete fusion of 

 intrazonal fibers. 



Quite recently Meves has published ^) a more minute account of 

 the general history of this structure; and his 'results, with respect to its 

 origin among the intrazonal spindle fibres of the previous division, will 

 be found to approximately accord with my own. Still later, Field has 

 found the Neben kern (archoplasm) to arise in the same way during 

 the spermatogenesis of the Echinoderms, so that I think we are now 

 fairly justified in assuming that wherever the archoplasm exists it is 

 always the derivative of the preceding spindle fibres. 



From other and more general considerations F. Hermann had 

 previously homologised the Nebenkern of the salamander's spermato- 

 cyte, not only with the „Nebenkern" described by Platner, but with 

 the "sphere-attractive" which Van Beneden and Neyt described '^) in 

 connection with the fertilization of the eggs of Ascaris; these struc- 

 tures thus become equivalent to one another, and it is in the acknow- 

 ledgment of their mutual equivalence that the extension of Hermann's 

 adopted term "archoplasm" indifferently to them all, finds its justifi- 

 cation. The discovery of the similar mode of origin of the mammalian 

 Nebenkern would seem to justify the extension of the term archoplasm 

 to this structure also; but in its case certain difficulties arise. The 

 archoplasm (sphere-attractive as originally desciibed) contains with in 

 its substance the well known "polar corpuscles" or centrosomes. These 

 structures form the archoplasmic centre during both the period of 

 dynamical disturbance relating to mitosis and of the resting condition 

 of the cell; in fact, the archoplasm becomes divided into two separate 

 masses, the spindle being a comparatively insignificant intervening 

 structure. The centrosomes are also centrally disposed with respect to 



^) Ueber eine Art der Entstehung ringförmiger Kerne und die bei ihnen zu 

 beobachtenden Gestalten und Lagen der Attractionssphäre. Inaug.-Diss. Kiel 1893. 

 2) Bull. Acad. Roy. Belg. Ser. 3. T. XTV. No. 8. 1887. 



