280 ALBERT KUNTZ 



Preparations of the former are, therefore, somewhat more satis- 

 factory for the study of the development of the sympathetic 

 nervous system than preparations of the latter. The present 

 study is based primarily on embryos of Thalassochelys caretta, 

 observations on embryos of Chelydra serpentina being introduced 

 wherever such introduction has seemed desirable. 



It is a real pleasure to express my obligations to Prof. G. L. 

 Houser for many helpful suggestions and for valuable criticism 

 during the progress of this investigation. I also desire to express 

 my indebtedness to Prof, F. A. Stromsten for the use of a large 

 number of embryos of Thalassochelys caretta which were col- 

 lected by him at the Dry Tortugas, Florida, during the summer 

 of 1910. 



As indicated in my earlier papers,^ the most satisfactory prepa- 

 rations for the study of the development of the sympathetic 

 nervous system were obtained from embryos which were fixed 

 in chrom-aceto-formaldehyde, sectioned to a thickness of 10 micra, 

 and stained by the iron-hsematoxylin method. This method 

 was employed almost exclusively in this investigation. 



The literature bearing on the development of the sympathetic 

 nervous system has been reviewed by the writer in an earlier 

 paper f therefore, only such references will be made to the litera- 

 ture in this paper as seem to be necessary. 



Observations on the development of the sympathetic nervous 

 system in reptiles are few and incomplete. According to C. K. 

 Hoffman ('90), the ganglia of the sympathetic trunks in reptiles 

 arise from cells which are derived directly from the spinal ganglia 

 according to the view first advanced by Balfour and later elabo- 

 rated by Onodi. Neumayer ('06) described the earliest anlagen of 

 the sympathetic nervous system in Lacerta (Spec ?) as slender cell- 

 strands growing ventro-mesially from the mixed spinal nerves. 

 As development advances these cell-strands become more con- 

 spicuous and terminate distally in distinct cell-aggregates which 

 constitute the anlagen of the ganglia of the sympathetic trunks. 



1 See bibliography. 



2 Tho (ievelopment of the sympathetic nervous system in mammals. Jour. 

 Comp. Neur. and Psych., vol. 20, no. 3, pp. 211-258. 



