Ivi PROCEEDINGS OF THE 



the superior intercostal artery and the upper aortic intercostals. It is 

 obvious that such a condition might easily be produced if the con- 

 striction of the aorta described above be enough to prevent a sufficient 

 supply of arterial blood passing into the descending thoracic aorta ; 

 and the great narrowing at this constriction, together with the bilateral 

 arrangement and convoluted course of the compensatory vessels, point 

 to such a conclusion. 



iii. Kidneys. — The abnormality in this region consists in the 

 union of the two kidneys across the middle line, to form a so-called 

 * horse-shoe ' kidney. Of the two elements, the left is three times 

 L/ the size of the right, and the greater part of both is situated within 



the false pelvis. The connecting portion, which is quite as broad 

 as the right kidney, is placed in front of the aorta, and has the 

 inferior mesenteric artery passing down on its anterior surface. The 

 pelvis of the left kidney is somewhat dilated, and occupied by a 

 large stone. That of the right is not so large, and is situated in front 

 of the inferior vena cava, immediately to the right of the middle 

 line. 



"With regard to the arterial supply, the left renal artery is three or 

 four times as large as the right. The right kidney, however, receives 

 a branch from the common iliac artery of that side, which runs 

 upwards to sink into its lower margin. There is no corresponding 

 branch present on the left side. 



A special branch springs from the front of the abdominal aorta, and 

 runs down to enter the substance of the connecting portion. 



(10) Dr T. R. W. Armour exhibited the Genito-urinary Organs of 

 a male Jerhoa (fig. 3). The chief interest of the specimen lies in the 

 character of the glans penis, in which a condition occurs similar to that 

 found in some reptiles, and among mammals, in certain rodents only, 

 e.g., guinea-pig. Agouti rat, and spotted cavy. 



The testicle is f inch long, and nearly i inch Avide ; it is connected 

 with the parietes by a mesorchium in which lie the spermatic vessels 

 and the tortuous vas deferens, the latter having a very narrow attach- 

 ment to the upper pole of the testicle, and swelling out into an 

 ampulla before joining the urethra. The bladder is small, and has 

 a relatively long thin neck, the upper portion of which is joined 

 by the two ureters. The membranous urethra is nearly an inch 

 long; at its upper end a small swelling, apparently corresponding 

 to the prostate, can be felt : at this point the vasa deferentia and 

 seminal vesicles join the urethra. The penis is 1^ inches in length; 

 it consists of the normal corpora cavernosa and corpus spongiosum, 

 the former diverging posteriorly as the two crura, and the latter 

 expanding at its ends to form the bulb and glans penis. The 

 bulb indicates on its surface a division into two hemispheres, and 

 attached to the urethra at its posterior border are well developed 

 Cowper's glands. 



The glans penis projects backwards into the cavity of the inversion 

 of the skin of the abdominal wall which forms the preputial sac, and 



