1897. 7^^^ SUPRARENAL BODIES OF FISHES. 321 



3. The segmental suprarenal bodies of elasmobranchs appear to be 

 wanting in other orders of fishes (with the possible exception 

 of Dipnoi), and correspond to the medulla of the suprarenal 

 bodies in higher vertebrates. 



From recent experiments made by Vincent (23-24) it would 

 appear that these really correspond, physiologically as well as 

 structurally. In teleosts the known suprarenal bodies appear to 

 consist entirely of cortical substance, since they have no physiological 

 action upon blood pressure, such as we know in connection with 

 medulla ; but that they are active secreting glands has been shown by 

 Pettit (15). The same condition appears to obtain in ganoids. 



In all higher vertebrates both portions are present, but combined 

 in one organ, and it seems very probable that each part fulfils its own 

 function, that of the medulla being to pour into the blood some 

 material or materials which maintain the normal tone of the muscles 

 throughout the body, while that of the cortex is yet unknown. 

 Vincent (23, p. 6) has suggested that the function of the cortex is to 

 manufacture and pour into the blood some substance which possesses 

 the power of getting rid of pigm.ents. He points out that in Addison's 

 disease, " when this part of the gland is damaged the necessary 

 secretion does not take place, and bronzing of the skin is the result." 



One might form two conjectures concerning the function of the 

 cortex : — (i) that it is in some way an accessory to the medulla, e.g., 

 that it prepares the material for final elaboration in the medulla ; or 

 (ii) that it is a totally distinct and independent gland, and its associa- 

 tion with the medulla is merely accidental. From a consideration of 

 the suprarenal bodies in the lower vertebrates, this latter view is the 

 one I personally take ; and I understand from Mr. Vincent that he 

 also is inclined to agree with it. 



The following table from my paper in the A natomischer A nzeiger 

 briefly summarises the distribution of the cortex and medulla in the 

 Cyclostomata and Pisces as known at present. 



SUPRARENALS. 



Cortex. Medulla. 



Cyclostomata . . . . Possibly degenerate. 



Elasmobranchu .. Interrenal .. .. .. Paired suprarenals 



HOLOCEPHALA . . . . do. . . . . . . do. 



Ganoidei . . . . Suprarenals in kidney . . Apparently absent 



Teleostei . . . . Suprarenals on kidney . . do. 



Dipnoi . . . . . . No suprarenals as yet described. Perirenal large-celled 



adenoid tissue ? (Vincent, 22). Certain bodies 

 described by Pettit (15), 



