294 S. Vincent, 



to spheies (PI. XVI. figs. 5 and 6). In most cases these vesicles 

 appear to be completely filled with cells, but in some cases, as in 

 the Anguillidae, they contain a distinct lumen (PI. XVI. figs. 5 and 6). 

 In the Anguillidae, perhaps, we have the most typical arrangement. 

 In these animals the suprarenal body consists of a mass of a closed 

 cylinders, of varying form (PI. XVI. figs. 5 and 6). On section 

 many of them appear rounded or polyhedral from pressure of neigh- 

 bouring cylinders, while others are more elongated, but never reaching 

 any very great length. The cylindrical alveoli are separated by a 

 loose connective-tissue in which runs a rich capillary plexus and 

 numerous lymphatic vessels. The alveoli are lined with cells usually 

 one row deep. These are columnar and contain a distinctly granular 

 protoplasm, and one, or sometimes two, nuclei. The cells are usually 

 18 — 20 i-i in length by 2 — 10 /t in width. They are of unequal 

 heights and have the appearances which are usually interpreted as 

 indicating a breaking down of the cell substance to form a secretion. 

 But it is doubtful if this is the true significance of what one sees. 

 It is more likely that the cells in their central portions are more 

 friable than elsewhere and more easil}^ break down under the razor. 



In some species (Orthag oris eus mola) the alveoli have the form 

 of branching tubules running in all directions (PI. XVII. figs. 8 and 9). 

 Thus the general appearance of the suprarenal bodies on section oifers 

 a considerable variation throughout Teleosts, but when closely examined 

 the difi'erences are found to consist (in addition to the form of the 

 acini already described) chiefly of variation in amount of fibrous tissue, 

 and variation in blood supply. 



From histological considerations I previously came to the conclusion 

 that the suprarenal bodies of Teleosts consist entirely of cortex [116, 

 117]. I have further tested tlie matter physiologically and chemically, 

 and find that the opinion then formed was correct [118, 120, 121, 122]. 

 There seems to he in Teleosts no equivalent to the paired bodies of 

 Elasmohranchs or to the medulla of the suprarenal capsules of the 

 higher Vertebrata ^). 



^) The question of the relation of the degenerated pronephros or so-called 

 "head-kidney" to the suprarenal bodies of Teleostean fishes I have sufficiently 



