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Show 716 MR. F. E. BEDDARD ON THE [Dec. 4, epigastric vein. Some years since I described * in the Echidna " a large vein running along the ventral wall of the body in very close connection with it," which I identified with the Anterior Abdominal Vein of the lower Vertebrata, and regarded as a persistent Allantoic Vein, persistent nowhere else among the Mammalia. I a m not quite certain whether Prof. Gegenbaur2 actually saw this vein himself two years later. But in any case he quotes its existence to emphasize the remoteness of the Monotremata from other Mammalia-" den Besitz einer Abdominalvene theilen sie mit Beptilien." This sentence seems to imply an agreement between Echidna and Ornithorhynchus, which is not the fact, as our principal authority upon the vascular system of the Vertebrata, Prof. Hochstetter, has quite recently pointed out3. In the paper referred to, the author entirely confirms m y discovery of the vein in Echidna, Avithout entirely pledging himself to the comparisons made by me. H e examined Ornithorhynchus with quite negative results. If the vein in question were present in that animal and happened to be turgid with blood, it could hardly, judging from my experience of Echidna, be missed, even in a spirit-specimen. But if not in this favourable state, it might conceivably be passed over. The matter therefore appeared to be worth looking into again, particularly since Prof. Howes has dealt with it from a far different point of view. Prof. H o w e s 4 has recently directed attention to the matter in connection with the visceral anatomy of the Australian Torpedo, Hypnos subnigrum. H e considers that the falciform ligament of the liver in mammals is a vestige of the continuous ventral mesentery preserved in the Dipnoi and Amphibia, and remarks as follows5:-" Beddard has briefly described (P. Z. S. 1884, p. 553) a median epigastric vein in the adult Echidna. It is most desirable that the relationships of this vessel should be more fully worked out. I cannot reconcile with this the belief (Balfour, Comp. Embryology, vol. ii. p. 623) ' that the falciform ligament is not a remnant of a primitive ventral mesentery.' Beddard's discovery would appear to m e fatal to this consideration, and it calls for a re-investigation of the matter." M y investigation of the fresh Ornithorhynchus fully bears out Prof. Howes's criticism of the late Prof. Balfour's opinion of the falciform ligament. I am also able to confirm Hochstetter's statement that the epigastric vein is wanting in Ornithorhynchus. The confirmation is of some little importance, as it might con- ] " Note on the Presence of an Anterior Abdominal Vein in Echidna," P. Z. S. 1884, p. 553. 2 ' Zur Kenntniss der Mammarorgane der Monotremen.' Leipzig, 1886. 3 " Ueber die Entwicklung der Abdominalvene bei Salamandra maculata," Morph. Jahrb. xxi. 1894, p. 26. 4 " On the Visceral Anatomy of the Australian Torpedo (Hypnos subnigrum), with especial reference to the Suspension of the Vertebrate Alimentary Canal," P. Z. S. 1890, p. 669. 5 Loc. cit. p. 673, footnote. |
