Vol. VI H. February, 1905. No. j 



BIOLOGICAL BULLETIN 



COMPARATIVE PHYSIOLOGY OF THE INVERTE- 

 BRATE HEART. 1 



WITH PLATES IV. TO VIII. 



A. J. CARLSON. 

 (From the Hull Physiological Laboratory, University of Chicago.) 



I. THE INNERVATION OF THE HEART. 



CONTENTS. 



PAGE. 



Lamellibranchs 125 



Chitons 129 



Diatocardic prosobranchs I3 1 



Monotocardic prosobranchs 132 



Tectibranchs 135 



Nudibranchs 1 40 



Pulmonates 143 



Cephalopods 1 46 



Decapod crustaceans i 150 



Arachnids 152 



Tunicates 155 



Before proceeding to describe the ganglia and the nerves that 

 make connection with the cardiac apparatus particularly in the 

 molluscs it seems necessary to make an explanation regarding 

 the nomenclature to be followed. There is no little confusion in 

 the terminology applied to the different ganglia and nerves con- 

 nected with the viscera and the respiratory organs in the mol- 



1 Part of this work was carried out at the Physiological Laboratory of Stanford 

 Universtiy, at the Hopkins Seaside Laboratory, Pacific Grove, Cal., at the Marine 

 Biological Laboratory of the University of California at San Diego, and at the 

 Marine Biological Laboratory, Woods Holl, Mass. ; and I am indebted to the direc- 

 tors of these several laboratories Professors Jenkins, Gilbert, Ritter, Whitman, and 

 Lillie for the privileges enjoyed. During the greater part of the time devoted to 

 the work I held one of the Research Assistantships of the Carnegie Institution of 

 Washington, D. C. The Carnegie Institution also placed one of the research rooms 

 at the Woods Holl Laboratory at my disposal during the summer of 1904. 



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