The Heart of the Sea- Turtle. 331 



What is depicted in Plate (fig. 1) as ganglion cardiacum 

 basale must be regarded as the results of the fusion of the 

 inferior cervical ganglion and the first thoracic (G-. stella- 

 tum). 



All of the ganglia, except this one, are very ill-defined 

 cordiform swellings, scarcely recognizable but for the 

 branches they give off. 



The accelerating branch from the middle cervical gan- 

 glion is very much more constant and very much better 

 defined even in C. my das than in the Terrapin. The branch 

 has not in my specimens ever been paired. 



The vagus ganglion on its main stem is slightly better 

 marked than the one corresponding to it on the sympathetic. 

 It gives off a very great number of strong branches to parts 

 below (fig. 2.)- 



The brachial plexus in the sea-turtle is exceedingly strong, 

 and forms an interlacement of great complexity. The 

 branches proceed from the fifth or sixth to the ninth 

 metamere. 



From the ganglion cardiacum basale, several branches 

 proceed upwards to the different parts of the brachial plexus, 

 and downwards to various parts, some of them probably to 

 the heart. 



YIII. Cardiac Acceleration by stimulation of the Sympathetic. 



1. Stimulation of the sympathetic above the middle 

 cervical ganglion produces no decided and constant effects 

 on the cardiac rhythm ; but influences the eye as in the 

 Terrapin and land tortoise, i.e., the lower lid is depresssed 

 and the upper lid elevated ; at the same time, the pupil is 

 moderately dilated. In consequence of the imperfect devel- 

 opment of the nictiating membrane in the sea-turtle, little 

 effect is seen in this structure ; the dilation of the pupil has 

 seemed to me to be less marked than in the Terrapin. It 

 has now been shown that in all the Chelonians the main 

 sympathetic has throughout similar functions, not only on 

 the heart but on the eye. 



2. Stimulation of the branch from the middle cervical 

 ganglion has produced more constant effects than the cor- 



