OCR Text |
Show 16 MR. F. E. BEDDARD ON THE [Jan. 16, forward prolongation, which is as long as, or longer than, the posterior region of the kidney. There is no break whatever between these two sections; and their appearance as regards texture and colour is identical. The thinner anterior part of the kidney may pehaps be a mesonephros, persistent in these young forms. On the two sides of the body the two kidneys differed very considerably in dimensions. The right kidney is, as in other Snakes, more advanced than the left kidney, and its anterior end actually passes a trifle beyond the gall-bladder and all but reaches the liver. This kidney is altogether 108 m m . long, of which 44 m m. belong to the posterior broad region of the gland, the slender anterior portion being thus much the longer. The right-hand kidney is altogether only 92 m m . long, and the broader posterior region is here the longer of the two sections, measuring as it does 48 mm. The slender anterior prolongation of each kidney is not, of course, to be confounded with the adrenal body. This latter is plainly distinguishable from the kidney-tissue by its yellow colour and different texture. It lies in the middle section of the anterior region of the kidney. The gonads were not visible in either specimen. But I believe them both to be females. This conclusion was arrived at owing to the nature of the gonad-ducts. These ducts were of comparatively large calibre and without the close windings of the male ducts Moreover they were prolonged forward in the case of the right-Hand one to a point anterior to the gall-bladder where the duct appeared to end freely. In the region of the anterior portion of the kidney the duct was attached by an evident though narrow mesentery to the substance of the kidney. The actual course of the gonad-duct of the right side is shown in the figure annexed (text-fig. 4, p. 17). Anteriorly it lies to the outside of the kidney. At the junction between the anterior more slender and the posterior stouter region of the kidney it crosses over and lies to the inside of the kidney. The diameter of this tube appears to m e to be too great to allow of its being identified with the sperm-duct. Another and, as I believe, very strong reason forbids this identification. To the inside of each kidney, along the anterior thinner region of that organ only, is a more slender duct than the gonad-duct, which, however, presents the same general appearance. This duct commences some way in front of each kidney, but the exact mode of its commencement I have been unable to ascertain. It follows the kidney fairly closely, lying on the opposite side to that occupied by the gonad-duct, to a point some little way in front of the junction between the anterior and posterior sections of the gland, and there gradually disappears. It seems to m e that this structure must be unquestionably homologised with the mesonephric duct; and if so, the gonad-duct can hardly be the sperm-duct. That it is the mesonephric duct seems to be necessary from the impossibility of identifying it with anything else ; and if so, then the |