I^ROCEEDINQS 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. IX, pp. 79-15S. Plates I-XV. July 31, 1907. 



DISTRIBUTION OF THE SUBCUTANEOUS VESSELS 



IN THE HEAD REGION OF THE GANOIDS, 



POLYODON AND LEPISOSTEUS. 



By Wm. F. Allen. 

 (From the Stanford Marine Laboratory, Pacific Grove, Calif.) 



CONTENTS. 



Pace. 



I. Introduction 80 



Material 80 



Method of Procedure 80 



History 82 



II. Distribution of the Subcutafieous Vessels in Polyodon 94 



1. Cephalic Sinuses and their Connections 94 



Cephalic Lymphatic Trunk 96 



Hyo-opercularis Sinus 98 



Hyo-opercularis Lymphatic Trunk 98 



Facial Lymphatic Trunks 100 



2. Branchial Lymphatics (Nutrient Branchial Veins.'') lOi 



Branchial Arch Lymphatics (Nutrient Veins.') 103 



Respiratory and Nutrient Branchial Arteries io6 



Dorsal and Ventral Endings of the Branchial Lymphatic Trunks 



(Nutrient Branchial Veins.?) 108 



Lymphoid Tissue Surrounding the Heart of Polyodon 108 



III. Distribution of the Subcutaneous Vessels in Lepisosteus 113 



Longitudinal Lymphatic Trunks , 113 



Pericardial Sinuses 114 



Occipital Sinus 115 



Branchial Lymphatic Sinuses 117 



Hyo-opercularis Sinus n8 



Cephalic Sinus 118 



Branchial Lymphatic Trunks (Nutrient Veins?) 119 



Inferior Jugular Vein 121 



IV. Deductions and Summary 121 



V. Explanation of Plates 126 



VI. I^ist of Abbreviations Used in the Fio^ures 155 



Proc. Wash. Acad. Sci., July, 1907. 79 



