98 Canadian Record of Science. 



on being caught were kept on the sea shore in a " turtle 

 pen," so arranged as to admit of free ingress and egress of 

 water. They were also fed on crabs, their natural diet. In 

 all, 20 specimens were employed, belonging to three species 

 Chelonia caretta (Loggerhead), Chelonia imbricata (Hawks- 

 bill), Chelonia midas (Green Turtle). By way of comparison, 

 experiments have also been made on a limited number of 

 specimens of the land tortoise (pyxis). 



The Sympathetic System of Nerves in the Marine Turtle. 

 — It is very remarkable that Chelonia midas in its cervical 

 and thoracic sympathetic should very closely resemble the 

 terrapin, but differ widely from 0. caretta and imbricata. 

 In the latter, the sympathetic in the neck runs widely apart 

 from the vagus and almost equals it in size. Its superior 

 and middle cervical ganglia are ill-defined cordiform swel- 

 lings, while the lower cervical and the first thoracic ganglia 

 are fused together to form the ganglion cardiacum basale. 

 The latter is very large and gives off upward many strong 

 branches to the brachial plexus, and downward to the lungs, 

 etc., and probably to the heart. 



From the middle cervical ganglia a strong branch passes 

 to the heart along the vagus. This is a cardiac accelerator. 

 The corresponding branch in the terrapin is much less 

 defined and often wholly wanting. 



Chelonia midas differs greatly from C. caretta and imbri- 

 cata, resembling very closely in its sympathetic system the 

 terrapin. The sympathetic in the neck is very much 

 smaller than the vagus, its ganglia well marked and it is often 

 more or less united with (though easily separable from) 

 the vagus. But a great difference is observed in the absence of 

 fusion of the lower cervical and the first thoracic ganglia. 

 These ganglia are in the terrapin often connected by an 

 annulus Vieussenii. 



Sympathetic Cardiac Accelerators. — Stimulation of the 

 branch from the middle cervical ganglion referred to above 

 leads in the sea turtle with greater constancy than in the 

 terrapin to acceleration of the rate, and especially augmen- 

 tation of the force ; of the beat of the heart. Also stimula- 

 tion of the ganglion cardiacum basale or the main chain 



