196 JOHN E. S. MOORE. 



the leucocytes of the larval salamander, exhibiting a metamor- 

 phosis, the known phases of which have been seen to closely 

 correspond with those in the larger and more easily elucidated 

 elements. Lastly, all the cells I have described are little 

 differentiated (or, at any rate^ their divisional phenomena are 

 not complicated by the presence of secondary structures 

 arising during the development of adult tissues), and the ease 

 with which the archoplasm (Nebenkern of Plainer) is dis- 

 cernible in such elements, has, I believe, been the sole cause of 

 its association more particularly with the reproductive ones, 

 when, in reality, it would appear to be an essential factor in a 

 type of indirect division wide-spread among the tissues of 

 Vertebrates and Invertebrates alike. 



In conclusion I must thank Professor Howes for his kind- 

 ness in allowing me the use of the Huxley laboratory, and for 

 many valuable suggestions during the progress of the work. 



DESCRIPTION OF PLATE XXI, 



Illustrating Mr. John E. S. Moore's paper "On the Relation- 

 ships and Role of the Archoplasm during Mitosis in the 

 Larval Salamander.^' 



Fig. 1. — Resting cell from the undifferentiated genital ridge of the sala- 

 mander, showing lobose archoplasm and central bodies. 



Fig. 2. — Ditto, showing central body ; the archoplasm undifferentiated. 



Fig. 3. — Ditto, showing (a) central body, {/j) medullary zone, (c) archo- 

 plasm, {d) the external radiation of the cell-mass. Hermann's treatment and 

 hajmatoxylin. 



Fig. 4. — Ditto, Hermann's treatment and triple orange stain. 



Fig. 5. — Ditto, Hermann's treatment alone. 



Fig. 6. — Ditto, showing duplicated archoplasm. Hermann's treatment 

 alone. 



Fig. 7.--Ditto. 



Fig. 8. — Two resting cells which have recently completed their division, 

 showing the relative position of the archoplasms and their external radiation. 



