PITUITARY AND SUPRARENAL BODIES. 89 



expanded into vesicles by its accumulation. The thymus has 

 already been described. The parathyroid, distinct from either of 

 the two preceding structures, is situated between them at this 

 point, and consists of closely packed columns of epithelium, which 

 look very much like gland tubules. This body is of considerable 

 vascularity, there being many capillaries around the tubules. 



Pituitary body. Rabbit, (p. 3, s. 22 & 24, c. P., m. B.) The 25 



organ is surrounded by a capsule of considerable thickness, and 

 consists of two portions. The anterior is developed from the 

 dorsal aspect of the pharynx, and the posterior from the ventral 

 aspect of the brain. The anterior portion is made up of almost 

 solid columns of cells, in which there is occasionally the appear- 

 ance of a lumen. These columns are separated by loose connective 

 tissue. Near the hinder end of this portion duct-like tubules, 

 lined by cubical cells occur, next to which large venous spaces 

 are found. The latter are accompanied by small lymph 

 nodules. The posterior portion consists of fibrous material, 

 mostly non-medullated nerve fibres, amongst which there are 

 scattered nerve cells. 



Suprarenal body, T.S. Man. (p. 11, s. 22 & 24, c. P., 

 q.m. B.) (L) A thin fibrous capsule surrounds the organ, the 

 interior of which is divided into cortex and medulla. The 

 latter occupies but little of the whole organ, and is of a more 

 open texture. (//) Recognise the vertical columns of cells of 

 which the cortex is composed, they present a somewhat glan- 

 dular appearance. In the outer part of the cortex, which is 

 known as the glomerular zone, the columns are wider than in 

 the inner or reticular zone, which forms the mass of the organ, 

 and the columns of cells do not intercommunicate to the 

 same extent. 



