CONTRIBUTIONS FROIM THE ZOOLOGICAL LABORATORY 



OF THE MUSEUM OF COMPARATIVE ZOOLOGY 



AT HARVARD COLLEGE.— No. 240. 



STUDIES ON THE PERIPHERAL NERVOUS SYSTEM OF 

 AMPHIOXUS. 



By Harriet Lehmann Kutchin. 

 Presented by E. L. Mark. Eeceived June 2, 1913. 



Table of Contents. 



Page 



Introduction 571 



Literature 572 



Material and Methods 572 



Dorsal nerves 574 



A. Nerves of the rostrum 574 



B. Nerves of the buccal region 579 



C. Nerves of the velum 589 



D. Nerves of the branchial region 593 



E. Nerves posterior to the atriopore 603 



F. Spinal ganglia 606 



G. Structure of the dorsal nerves 607 



H. Sensory endings of dorsal nerves 608 



Ventral nerves 615 



Bibliography 621 



Explanation of figures 626 



Introduction. 



The literature on the nervous system of Amphioxus presents such 

 divergence of opinion that it is probable many facts with regard to the 

 structure, distribution and functions of this system still remain to be 

 determined and illustrated. It will be impossible to more than theo- 

 rize as to the primitiveness or the degeneracy of the nervous s^^stem of 

 Amphioxus until the main features of its organization are more 

 clearly understood. The present research aims to contribute toward a 

 knowledge of the structure and distribution of the peripheral nerves, 

 and it is hoped may aid in furnishing a basis for comparison with 

 other vertebrates. 



The following studies were undertaken in 1904 by the writer while 

 holding the Alice Freeman Palmer Fellowship of Wellesley CollegCi 



Contributions from the Bernuida Biological Station for Research. No. 28. 



