222 CLASS XV. 



expand in some degree before ending in tlie cloaca ; there is no 

 urinarj bladder. In the crocodiles also, and some other lacertine 

 animals, the urinary bladder is wanting, although it is present in 

 most of the other lizards as well as in the tortoises and the 

 naked amphibians * . 



According to the discovery of Jacobson veins run on the out- 

 side of the kidney, which, like the portal vein in the liver, divide 

 like arteries in the kidney [vence renales adveltentes) . These venous 

 stems are formed by the veins of the posterior parts of the body, 

 of the tail in serpents, and in other reptiles of those also of the 

 hinder limbs ; a part only of the venous blood of these parts goes 

 immediately to the cava or to the liver. The blood from the renal 

 arteries and afferent renal veins is returned by other renal veins 

 (eiferent) to the vena cava^. Supra- renal capsules {renes succentu- 

 riati) are found in most reptiles, generally however small and often 

 remote from the kidneys, situated on the inside of the kidneys 

 near the efferent veins ^. 



^ In the tortoises and frogs the urinary bladder is broad and is divided into two 

 lateral parts, which in the last are very spacious and with thin walls. ToWNSON (Observ. 

 pht/siol. de Amphibiis, Getting. 1795, p. 29) and Jacobson (Meckel's Archiv f. d. 

 Physiol. III. s. 148) have not been willing to recognise as urinary bladder the part 

 previously so named ; that the ureters do not terminate in this bladder is no reason for 

 assigning to it any other office ; even in the tortoises the ureters run to the neck 

 of the bladder or to the urethra itself, and thus the urine, like the bile in the human 

 gall-bladder, can in no other way reach the bladder than by that of regui'gitation. On 

 the kidneys of reptiles J. F. Link De Amphihiorum systemate uropoetko, Halte, 181 7, 

 Svo, may be consulted. The urine of serpents is a consistent white substance which 

 hardens on drying. 



- Compare L. Jacoeson De systemate venoso peculiari in permidtis animalibus ohser- 

 vato. Hafnise, 1821, 4to. See also the experiments with ligature of the afferent veins 

 of A. De Maetino Ann. des Sc. nat. 1841, Tom. xvi. Zool. pp. 305 — 309, and 

 especially Bowman's description of the 'portal system' of the kidney of the boa in his 

 memoir On the structure and use of the Malpighian bodies of the kidney, Phil. Trans. 

 1842, Pt. I. p. 64, PI. IV. fig. 17. 



■* In the European fresh-water tortoise they lie on the inside of the kidneys, 

 BOJANUS Anat. Testud. figs. 186, 188 P. In the frog the yellow or orange- coloured 

 bodies situated above the kidneys and divided into elongated finger-shaped slips, were 

 formerly supposed to be the supra-renal capsules. Eathkb and Retzius, on the 

 contrary, regard as representing the supra-renal capsule yellow bands composed 

 of granular matter that lie on the abdominal surface of the kidneys along the principal 

 branches of the efferent veins; see Nagel in Mueller's Archiv, 1836, s. 380, Taf. xv, 

 fig. 4, Gruby 1. 1. pp. 218 — 220, PI. 10, figs. 8— ro. 



