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Show 146 PROF. W. N. PARKER ON THE LEFT POSTERIOR [Mar. 19, the corresponding precaval, while posteriorly it opens into the postcaval just at the anterior border of the kidneys, sending an anastomosing branch to the renal portal. Professor Howes informs me that he has since come across another Frog in which a similar arrangement occurred, except that the azygos here entered the subclavian instead of the precaval. A week or two ago, while examining a number of specimens of Fig. 1. The venous system of an adult male Frog (Nana temporaria), in which the left posterior cardinal vein persisted, and the postcaval was absent. From the ventral aspect, X 2. cd, left cardinal vein ; h.v, hepatic veins; A; kidney ; Ir, liver; pr.c, precaval ; r.cd, vessel formed by the union of the posterior part of the two cardinals, and which normally gives rise to the inter-renal portion of the postcaval; r.p, renal-portal vein ; r. v, revehent renal veins ; sp, spermatic veins ; s.v, sinus venosus ; ur, ureter ; v.s, vesicula seminalis. Rana temporaria during a class demonstration, I found that in one of them (a male) the embryonic state of the veins was retained to a still greater extent than in the cases quoted above (see fig. 1). A large vein (cd), having similar relations to that described and figured by |
