THE DUCTLESS GLANDS 



315 



blood supply, from which it is separated by a thin layer of tissue. Its 

 distal end is in contact with the distal end of the cell opposite, and 

 although there is no lumen visible, there is a tendency for the collection 

 of secretion granules in the distal cytoplasm. In another fish, the conger, 

 as figured by Vincent, a lumen does occupy this region and probably 

 acts as a store for materials, as in the thyroid gland. 



In higher forms we find the two tissues, just described in the skate, 

 placed in varying degrees of proximity to each other. In the teleost 

 fishes the cortical portion is large and separated from the very small 

 amount of chromaffine tissue. In the Amphibia the two are in closer 



FIG. 283. Portion of a section through the adrenal gland of a fowl, Callus domesticus. 

 ch.c., chromaffine cells; c.c., cortical cells. X 1000. 



relation on the ventral surface of the kidney, while in the Sauropsida 

 they are mingled closely in a single gland whose position much resembles 

 that of the mammals. 



Figure 283 shows a section of the adrenal body of a bird, Callus domes- 

 ticus, in which one can recognize the larger mass of cords composed of 

 cortex cells, while among them at intervals appear smaller groups of 

 chromaffine cells. The cortex cells show no lumen in their cords, although 

 they are arranged so that every mass is double. Some cells are even 

 placed in a cord, so that they do not have access to the blood supply. 

 The body of such a cell must act in syncytial unison with that of the 

 cells which do touch the blood vessel. 



In the mammals the two adrenal tissues are placed close together, the 



