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Show 1890.] VISCEaAL ANATOMY OF THE AUSTRALIAN TORPEDO. 669 4. On the Visceral Anatomy of the Australian Torpedo (Hypnos subnigrum), with especial reference to the Suspension of the Vertebrate Alimentary Canal. By G. B. H O W E S , F.Z.S., F.L.S., Assist. Professor of Zoology, R. College of Science, S. Kensington. (From the Huxley Research Laboratory.) [Received December 2, 1890.] (Plate LVII.) The Australian Torpedo, Hypnos subnigrum, was first described by A. Dumeril1 from two specimens, deposited in the Paris Museum by Mons. J. Verreaux. Its skeleton has been dealt with by Haswell2, and has been shown to be in some respects exceptional and peculiar, while its electrical organs have recently been written about by G. Fritsch, in the second volume of his ' Die elektrischen Fische'3. During the Fisheries Exhibition held at South Kensington in 1883, M r . Ramsay, Curator of the Sydney Museum, brought some specimens of this fish to Europe ; three of thetn are now in the M u s e u m of Natural History, two (a c? and a $ ) in m y teaching collection at South Kensington. For the gift of these animals, zoologists at home owe M r . Ramsay and the authorities of his M u s e u m a debt of gratitude. O n laying open the post-pericardiac body-cavity of this fish, the alimentary tract is seen to be disposed in the manner of an inverted S, as is the case in all the lchthyopsida and the lower Amniota. That is to s a y - a line (a, 3 oi Plate LVII. fig. 1) drawn parallel with the long axis of the body would bisect the oesophagus and cloaca, together with a more or less considerable portion of the large intestine, and leave the stomach (cd., py.) to the left aud the small intestine (i.s.) to the right of the animal. The liver (hp.), which is two-lobed4, lies, as usual, ventrad of the stomach on the left side, and to the right and dorsad of the small (valved) intestine (i.s.") on the opposite one. Its gall-cyst (c.b., so called gall-bladder) is exceptionally spacious and lies disposed in a notch of the right lobe. This right liver-lobe is m u c h the larger of the two, and it extends inwards in this fish to an unusual degree, reaching almost to the middle line and forming (as seen from beneath) a kind of bed upon which the valved intestine lies. The latter, which, unlike that of most Chondrichthyes,bears no well-marked external furrows denoting the course of its contained valve, has the customary proportions and relationships, but that its duodenal segment (or Bursa Entiana, i.s.') is more tubular than is usually the case, Lcemargus excepted 5, and is marked off from the stomach 1 Eev. et Mag. de Zoologie, 1852, no. 5, p. 277. 2 Proc. Linn. Soc. N. S. W . vol. ix. part 1. 3 Leipzig, 1890. 4 As in Trygon, Urolophus, and Myliobatis, Haswell, Proc. Linn. Soc. N.S.W. vol. iii. (ser. 2), p. 1716. 6 P RCfO.C .T uZrnOeOrL,. J Souorcn.- A1n8at9.0 &, PNhoy.s .X vLolV. .vi i. p. 233 (1873).4 5 |