ERIK AGDUHH: "Is the posiembryonic growth of the nervous system due only 



the number of i 







Proeccdinfis Royal Ac;id. Amsierdain. V..I. XXI. 



EXPLANATION OF FIGURES. 



igures 1. 2. 4, 5. 6, 9. 10. II. 22. 23. 24 an 

 r?. immiTs. ' i; and ocul. 4 and using Reichi 

 igures 3. 7, 8, 12 and 2ti ate drawn after rr 

 m. Apari. 1.3 and Comp. ocul. N". 6. with 

 igures 13. 14, 15, 16, 17, 18, 19. 20 and 21 

 chr. imm,, 2 mm. Apart. 1.3 and Comp. 

 nng apparatus. 



ally. Thi*. small distinct collum-formal 

 2, Repr. ■/.., Gangl. spin. (Fix. and 

 ;ction scries as in fig. I. u. Ganglio 



I 25 are drawn after magnifying will 

 RT's drawing apparatus, 

 ignifying with Zeiss apochr. immers, 

 he help of Abbe's drawing apparatus 



rel I 



. (Siiv, 



regnated according to the BiELSCHOWSKY- 

 iclhod with my own modificalions) of a six days* old dog. a. Ganglion cell dividing 

 milolically, A, Ganglion cell with the beginning of amitotic division of the nucleus. 



Fig. 4. Repr. "i. Gnngl. spin. (Impr. as in fig. 3) of a sixty days' old dog. </. Colony 

 f apolar cells. Between the three cells in the middle there are bridges of protoplasm. 



Fig. 5. Repr, "i. Gangl. spin. (Fix. and staining as in fig. 1) of a 17 days' old dog 



Bipolar ganglion 



Fig. 13. Repr. "/a. Spinal cord (Fix. and stain, as in fig. 1) of a full-grown M. muse. v. alb. 

 An example of fairly frequently occurring indentations on nuclei of nerve cells: in 

 my opinion these indentations have very probably no connection with amitotic division. 



Fig. 14. Repr. 'j. Spinal cord (Fix. and stain, as in fig. 1) of a ten days" old Mii.t 

 miiscuhts V. albus. An example of a stage in amitotic!?! division in which the nuclei 

 are quite separated but the protoplasmic body is not quite divided. 



Fig. 15. Repr. %, Spinal cord (Fix. and stain, as fig, \) of a ten days' old Mm 

 muse. var. alhus. Cell plasmoditim or syncytium, situated just ventrally uf the canalis 



Fig. 20. Repr. 'h. Spinal cord (Fix, and slain, as in fig. IJ of a 24 days' old M. 

 muse, t: alb. A young nerve-cell in a far advanced stage of direct division. 



Fig. 21. Repr. 'h. Same material as in fig. 16. Young nerve cells from the base of 

 the dorsal horn in a very far advanced direct division into four. 



Figs. 22. 23 i.nd 24 are probable and tigs. 25 and 26 



the 



lethod. 



