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JEREMIAH S. FERGUSON 



ing finer twigs into the interior. In this particular they offer an 

 interesting analogy to the condition found by Major ('09) in 

 man. Major says (page 484), "in the human the branching of the 

 large arteries takes place mostly upon the surface of the gland, 

 and having by their branching obtained their approximate dis- 

 tribution, the smaller branches are sent in." In the Elasmo- 



Fig. 3. Outline of the arterial supply of the thyroid gland of Mustelus canis 

 as usually found. The vertical shading indicates the area supplied by the right 

 thyroid artery, the horizontal shading that supplied by the left. 



Fig. 4. Showing the less usual distribution of the thyroid arteries; the shading 

 as in fig. 3. 



branchs the condition might well be described in the same words; 

 this is the more remarkable inasmuch as Major states that this is 

 not the condition in other mammals, e.g., the dog and cat. The 

 Elasmobranchs, therefore, seem to harmonize with the human 

 rather than the lower mammalian condition as regards the dis- 

 tribution of the main branches of the thyroid arteries. 



