No. 3.] THE PROTOZOA AND METAZOA. 759 



cases two distinct granules were seen in this space. These 

 granules occupy various positions in relation to the membrane, 

 and in some cases they were found outside of the nucleus and 

 in the sphere. The inference is therefore drawn that the 

 centrosome is a permanent cell organ, which is not found in the 

 resting sphere, but in the nucleus, from whence it becomes 

 extra-nuclear by a rupture in the nuclear membrane. The 

 observations on this head are not conclusive, owing to the 

 smallness of the objects and to the presence of many similar 

 cytoplasmic microsomes. 



Columbia University, 

 November, 1897. 



Appendix. 



Since the above was written a number of forms have been 

 carefully examined in the hope of finding Protozoa in which the 

 archoplasm may be traced back to a type still more primitive 

 than Eiiglcna viridis. It was found that Trachelomonas hispida, 

 T. volvocina, Microglena punctifcra, and Synura uvella have 

 nuclei similar to that of EiigUna viridis ; i.e., with a central 

 body and chromatin in the form of small granules. In another 

 set of forms, including Trachelomonas lagenella, T. hispida 

 (variety), and Chilonionas cylindrica, the chromatin is in the 

 form of granules and, as in Eitglcna, surrounds a central body, 

 but, unlike Eiiglena, there is no nuclear membrane. Finally, 

 in a species of Tetramitus, not only is the nuclear membrane 

 absent, but the granular chromatin is distributed throughout 

 the cell, and only during division are the granules collected 

 around a central body. This central body corresponds evidently 

 to the Nebenkorper of the flagellate-stage of Schaudinn's Para- 

 moeba Eilhardi, but in Tetramitus, except during cell division, 

 it is cytoplasmic, no morphological nucleus being present. The 

 relations of this body to the chromatin are the same as the 

 relations of the sphere to the chromatin in Noctihica, although 

 the former is far more primitive because of the distributed 

 nucleus (cf. Bacteria). It would seem, therefore, that archoplasm 

 was originally cytoplasmic ; that it attracts (.') the chromatin 

 about it during cell division {Tetramitus); that, in somewhat 



