54 CALIFORNIA ACADEMY OF SCIENCES. [3D Ser., 



often striking, as, for instance, in fig. 65. The somosphere 

 is probably identical with the faintly staining sphere sur- 

 rounding the microsomes in Heidenhain's figs. 37, 39, 48, 

 49> 53, etc. 



If we compare our cytoplasmic spheres with the gang- 

 lionic cells of the frog, as described by Lenhossek, we 

 find several points of similarity. Lenhossek endeavored to 

 harmonize the cytoplasmic spheres seen by him with those of 

 other investigators, and met I think with some success. He 

 divides the cytoplasm into two main divisions; an outer one, 

 for which he proposes the name plasmosphere or perisphere, 

 and an inner division which he refers to as centrosphere, 

 the latter being sharply defined like a second nucleus. This 

 agrees exactly with the centrosphere of the plasmocyte, and 

 I have for this reason adopted the name proposed by Len- 

 hossek for this highly individualized part. The centro- 

 sphere of Lenhossek is frequently surrounded by a white 

 ring, a fact which I, too, have observed at times in the plas- 

 mocytes. A study of Lenhossek's figs. 5, 6, 7, and 9 shows 

 that the minute centrosomes are surrounded by a dark film 

 which I identify with my somosphere. As regards the 

 plasmosphere of the ganglionic cells the agreement is less 

 apparent, except that the cytoplasm is prominently concen- 

 tric and consists of at least two, probabhy three, dis- 

 tinctly differentiated zones, which, however, are not strictly 

 localized. Of these the inner zone is granulated, while the 

 middle one (Lenhossek, Tan. xv, fig. 3), stains even more 

 intensely than the granosphere of the plasmocyte. In the 

 ganglionic cell as well as in the plasmocytoblast it is the 

 " grosse gekornte Protoplasmaschicht " which causes the 

 dell in the nucleus, a fact which when coupled with other 

 similarities warrants my identifying these two zones with 

 each other. 



In one of the very latest contributions to cytology, Dr. O. 

 Van der Stricht has described cell structures which bear a 

 marked resemblance to those of the plasmocytoblasts. In 

 his figs. 19, 20, 21 and 22, but especially in 19 and 20, we 

 find a most striking arrangement of the cytoplasm. It be- 



