218 Relation of Nervous S3'steni to the Developing Mnsculatnre 



ments on the sense organs of the lateral line, after destruction of their 

 nerve supply/ bear out the correctness of this view. 



Long ago Eoux, 8i and 85, suggested "that the development of the 

 organism colild be divided into two periods, the one an organ-forming 

 period and the other one of functional development. In the first the 

 organs are formed and brought to that condition in which they are capable 

 of beginning a specific function ; in the second period, in which the organs 

 exercise their specific function, their further perfection is helped by this 

 activity and interfered with by its absence. While the general aptness 

 of this distinction is apparent, the present study shows that there is not 

 only an overlapping of the two stages in different systems of organs, as 

 Eoux pointed out, but also in the same organs ; even in one and the same 

 muscle fiber, as shown above, the tendencies of the two periods may mani- 

 fest themselves side by side. It must nevertheless again be emphasized 

 that all of the constructive processes involved in the production of the 

 specific structure and arrangement of the muscle fibers take place inde- 

 pendently of stimuli from the nervous system and of the functional 

 activity of the muscles themselves. 



LIST OF REFERENCES. 



Bardeex, Charles Russell, oo- — The Development of the Musculature of the 

 Body Wall in the Pig, including Its Histogenesis and Its Relations to 

 the Myotomes and to the Skeletal and Nervous Apparatus. The Johns 

 Hopkins Hospital Reports, Vol. IX. 



02. — Embryonic and Regenerative Development in Planarians. Biol- 

 ogical Bulletin, Vol. III. 



03.7— Factors in Heteromorphosis in Planarians. Archiv fiir Entwickel- 



ungsmechanik, Bd. 16. 



Barfurth, Dietrich, 01. — 1st die Regeneration vom Nervensystems abhangig? 

 Verhandlungen der Anatomischen Gesellschaft, Bonn, 1901. Anatom- 

 ischer Anzeiger, Bd. 19. 



Buck D. de et Moor, L. de, 03. — Morphologie de la Regression Musculaire. Le 

 Nevraxe, Vol. 5. 



Driesch, H., 01. — Neue Antworten und neue Fragen der Entwickelungsphysiol- 

 ogie. Ergebnisse der Anatomie und Entwickelungsgeschichte, Bd. 11, 

 1901. 



Fraser, a., 95. — Various Morphological Papers, III. On Various Single and 

 Double Monstrosities, with Remarks on Anencephalic and Amyelic 

 Nervous Systems. Trans. Royal Academy of Medicine, Ireland, Vol. 

 12. (Cited according to Schaper.) 



Harrison, Ross G., 03- — On the Differentiation of Muscular Tissue when Re- 

 moved from the Influence of the Nervous System. Proc. Ass. Amer. 

 Anatomists, American Journal of Anatomy, Vol. 2. 



* Harrison, 03a, p. 72. 



