VASCULARITY OF THE HYPOPHYSIS OF LOWER VERTEBRATES: THE PAINTED TURTLE,CHRYSEMYS PICTA MARGINATAAGASSIZ

Abstract

Measurements were made on the diameter and length of the capillaries of the turtle hypophysis. The volume and surface of vessels were calculated and compared with those of the cat, frog, and salamander. Only the anterior lobe showed vessels which were significantly wider than in the adjacent brain tissue. The surface area of blood in the anterior and tuberal lobes is very extensive, 17 sq. mm. to 18 sq. mm. for 1 cu. mm. of fresh tissue, and is between two and three times as great as in the other lobes and in the richest centers of the brain. The vascular surface in each lobe, except the intermediate one, is lower than, but shows similar variation to, that of the cat. The pars nervosa is supplied by vessels between it and the pars intermedia as in the salamander and is unlike that of the frog or cat with numerous vessels penetrating its substance.