1885.] VISCERAL ANATOMY OF BIRDS. 839 



The dissection of two specimens oi Rhea americana which liave 

 died during the course of the present year, enables ine to confirm the 

 above-mentioned statements. In this bird, however, and in the 

 Ostrich, the two cavities which contain respectively the ri^ht liver- 

 lobe and tlie left liver-lobe, together with the gizzard, are floored by 

 a tough membrane, which, behind the gizzard, becomes superficial, 

 and covers over the coils of the intestine ; this membrane is attaclied 

 laterally to the body-wall and to the " oblique " septa which form 

 the inner boundaries of the posterior intermediate air-sacs. 



In the Emu (Dromaus) there is a close similarity to the con- 

 dition met with in Strulhio and Rhea. 



On opening tlie hird by a median incision through the abdominal 

 parietes, and reflecting the two cut halves of the musculature, the 

 disposition of the viscera was seen to be practically identical with 

 that of the other Struthiones. A tough membrane covers over the 

 posterior section of the abdominal cavity ; just behind the gizzard 

 this membrane is firmly attached to the oblique septum ; posteriorly 

 it appears to be also attached to the oblique septum, but the two 

 structures are in reality separable, and the horizontal membrane of 

 the abdomen is continued upwards to the middle line of the body, 

 where it is attached firmly in the neighbourhood of the spinal column. 



The right lobe of the liver, as in Stritthio and Rhea, is enclosed in 

 a separate pocket of peritoneum, and the left lohe appears to be con- 

 tained witliin another cavity common to itself and to the gizzard ; 

 a more minute examination, however, has convinced me that the 

 gizzard is in reality enclosed in a distinct compartment, and is firmly 

 attached to the parietes, as Prof. Huxley has stated of the gizzard 

 of the Ostrich. Whether this is also the case with Rhea, I am 

 unable to state. Mr. Parker has said nothing of the attachment of 

 the gizzard to the parietes, and my own notes upon the sultject are 

 unfortunately not sufficiently explicit. There is, as Prof. Huxley 

 has shown, a close correspondence in many of these points with the 

 structure of the Crocodile. 



In the OvocoihXe {CrocoJilus acutus) (see fig. 1, p. 840) the viscera 

 have the same relative position; the two lobesof the liver lie anteriorly, 

 the gizzard is situated on the left side of the body behind the left 

 lobe of the liver, wliile the intestines occupy the rest of the abdominal 

 cavity. On opening the body-cavity the intestines are not visible ; 

 they are in fact covered and concealed by a horizontal septum which 

 runs from side to side of the body, this septum loosely covers the 

 intestinal cells, it is not attached to them anywhere, but arises from 

 the abdominal parietes ; anteriorly this membrane is firmly attached 

 to the gizzard, and in fact divides into two layers which enclose and 

 completely shut off that viscus from the rest of the abdominal cavity. 

 The two lobes of the liver are likewise separated from each other 

 and from the gizzard and the rest of the abdominal cavity by septa 

 of fibrous tissue. Tiie arrangement of the abdominal viscera in the 

 C/rocodile is therefore practically the same as that which I have 

 just described in Droma;us ; in both animals the intestinal coils are 

 loosely covered by a horizontal membrane, and in both the two lobes 



