78 MK. SWALE VINCENT ON THE 



anterior end which reaches far into the head. So that this species must be added to 

 the list of those which have no purely lymphatic head-kidney. 



4. Function of the Lymphatic Head-Kidney. 



I am convinced that the appearances above described (blood-corpuscles free in the 

 tissue spaces, crystals of oxy-heemoglobin and other derivatives of haemoglobin) point 

 to a blood-destroying function of the lymphoid anterior end of the kidney, and very 

 possibly also of the rest of the intertubular material, and this appears not unreasonable 

 since lymphatic glands in Man can probably carry on this function. They appear to 

 do so, at all events after removal of the spleen, and it is not conceivable that an organ 

 should be able to take on in an emergency duties which it had never performed to the 

 slightest extent previously 1 . 



5. Relation of the Suprarenals to the Head-Kidney. 



1 have already sufficiently disproved the idea that where one of these is present the 

 other is absent. I have further, by careful measurements, attempted to make out if 

 there were any inverse ratio between them as to respective bulk, but in this I have 

 failed entirely. So that I am forced to conclude that there is no anatomical relationship 

 whatever between them. 



Physiologically one cannot be so certain, but it seems very likely that the head- 

 kidney functionates as a lymphatic gland, while the suprarenals, in all probability, are 

 secreting-glands, which minister to the needs of the blood, just as in the higher Verte- 

 brates. Functional relationship is, then, equally improbable. 



Grosglik (29) considers that the head-kidney of adult Teleosts consists of two parts, 

 the degenerated pronephros and the cortical part of the suprarenals, and that the 

 known suprarenals of Teleosts correspond to the medullary substance in the Amniota 2 . 



It is certainly curious that we find the lymphatic head-kidney just in those cases 

 where only one portion of the suprarenal appears to be represented. But, in my 

 opinion, the part which is not represented in Teleosts and Ganoids is the medulla and 

 not the cortex, so that, if the head-kidney has anything to do with the suprarenals at 

 all, I should expect that it would represent the medulla. But, satisfactory as such a 

 conclusion would be, I cannot find any grounds for it whatever. There is nothing in 

 the structure of the degenerated pronephros which suggests any connection with supra 

 renal structure of either kind. 



The question as to the physiological correspondence of the suprarenal in Fishes to 

 the organs in higher Vertebrates, I hope to have the opportunity of settling at an early 

 date by means of direct experiment 2 . 



[It has been mentioned above that Balfour considered the function to be that of formation of red 

 corpuscles. This view has also been held by Emery (26), and Bizzozero and Torre, Mem. Accad.Lincei Roma, 

 vol. xviii. 1883-84.— S. V., 10. 1. 97.] 



2 An t. Anz. xiii. Bd. Nr. 1 & 2 (1897). 



