THE HEART AND ARTERIES OF POLYODON 



C. H. DANFORTH 



Fro7n the Department of Comparative Anatomy of Harvard Medical School 



NINETEEN FIGURES 



The following account of the arterial system of the ganoid 

 Polyodon was begun in the Anatomical Department of Washing- 

 ton University and completed in the Department of Compara- 

 tive Anatomy at Harvard Medica School. The writer grate- 

 fully acknowledges his indebtedness to the staffs in both places. 

 The work is approached entirely from a morphological viewpoint 

 and only the gross anatomical relationships are considered. The 

 material used has been chiefly fish of about a meter in length 

 which were secured in the vicinity of St. Louis. These were 

 injected with gelatin and starch masses, the latter proving quite 

 satisfactory for present purposes. The results have been checked 

 by a study of serial sections of a 74 mm. specimen which has 

 already been briefly described by the writer (Danforth, '11). 



Allis's ('11) paper on the pseudobranchial and carotid arteries 

 of Polyodon did not appear until the present work had been 

 finished except for the drawings. Since that paper only par- 

 tially covers the field attempted here and moreover some com- 

 parison of our results seems desirable the paragraphs on the 

 pseudobranchial and carotid vessels are retained without very 

 much condensation. 



PERICARDIUM AND HEART 



The pericardium has the usual conical or rounded form with 

 the base directed caudally against the septum transversum. 

 A dorsal and two lateral faces are vaguely indicated. The lin- 

 ing is a uniform serous membrane with no macroscopic openings 

 except that of the pericardio-peritoneal canal. This is a rather 



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