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Show 1885.] VISCERAL ANATOMY OF BIRDS. 841 Crocodile and the Struthiones is not, however, confined to these members of the latter order. Other birds present an identical series of structures. I will now proceed to review these in detail. The most complete resemblance to the Struthiones is to be found, so far as m y dissections enable m e to say, in the Cranes ; and from a classificatory point of view these resemblances appear to m e to have some significance. I have dissected two species of Cranes, Grus communis and G. monachus, and the following description applies equally well to both. The gizzard and the left lobe of the liver are enclosed in a separate compartment of peritoneum ; the right lobe of the liver is in another compartment, separate from the left lobe by the vertical septum or umbilical ligament, which runs back for some way, and is in close contact with the right-hand margin of the gizzard. The intestines are covered by a horizontal membrane, which is attached anteriorly to the gizzard, and in fact clasps it round its whole circumference, so that the upper half of the gizzard projects into the abdominal cavity containing the intestinal coils ; the gizzard, at least its upper surface, appears to be surrounded by a layer of peritoneum reflected from the horizontal septum. The disposition of the viscera and the various septa is therefore identical with that of Rhea and Dromaus, and almost identical with that of the Crocodile. In an interesting paper on the anatomy of the Flamingo1, M r . Weldon has referred to the presence of an exactly similar horizontal septum, which he terms "pseudepiploon," in this bird and in many Storks; he describes it in the following words : - " O n slitting open the abdominal wall of a Stork in the middle ventral line, the only viscera exposed are the two lobes of the liver and the ventral portion of the gizzard. All the rest are hidden by a thick horizontal septum of connective tissue, stretching across the whole body-cavity from the pericardium to the cloaca." It is evident from this quotation that the disposition of the viscera in the Stork is closely similar to what has just been described in the Crane, and only differs in that the lobes of the liver are not enclosed in special compartments of their own. They are stated to be visible on opening the body-cavity, while in the Cranes and Struthious birds the lobes of the liver are not so visible, but require a further dissection of the walls of the compartments which contain them. I have dissected another form of Storks, Abdimia sphenorhyncha, in addition to many of those mentioned by M r . Weldon, and find that the conditions are identical. The Spoonbill (Platalea leucorodia) is a Stork, in so far as the above-mentioned characters are concerned ; I believe that the general consensus of opinion is to regard this bird as closely allied to the Storks, and the foregoing considerations confirm this view. In Bucorvus abyssinicus (fig. 2, p. 842) the septa are in the main similar to, but present certain variations from, the types which have been already described. On opening the body-wall the gizzard was 1 P. Z. S. 1883, p. 639. |