1886. ] ON THE AIR-SACS OF THE CASSOWARY. 145 
3. Note on the Air-sacs of the Cassowary. By Franx E. 
Brepparp, M.A., F.R.S.E., Prosector to the Society. 
[Received March 1, 1886.] 
The following note refers to a male Casuarius uniappendiculatus 
which died in the Society’s Gardens on February 15th of the 
present year. 
Since no description of the respiratory organs of this bird has, so 
far as I know, been published, I have thought it worth while to bring 
a note upon the subject before the Society, to supplement Prof. 
Huxley’s paper upon the respiratory organs of Apéeryx' and Prof. 
W. N. Parker’s ‘ Note’ upon the same structures in Rhea *. 
As regards its air-sacs the Cassowary appears to resemble Apteryx 
much more closely than Rhea, though differing slightly from the 
former. In dpteryx the main difference in the air-sacs from those 
of Carinate Birds is in the small extent of the abdominal air-sac. 
“In Apteryx the whole of this sac is enclosed between the oblique 
septum and the pulmonary aponeurosis, the dissepiment between 
its loculus and that of the posterior intermediate sac being situated 
almost midway between the second dissepiment and the posterior 
extremity of the pneumatic chamber. In the Duck, on the con- 
trary, the dorsal end of this dissepiment~is attached close to the 
posterior extremity of the lung, and thence slopes very obliquely 
backwards. ‘The capacity of the posterior intermediate air-sac thus 
becomes greatly increased. But, as the capacity of the posterior 
air-sac is also vastly greater than in dpéeryz, its posterior wall has 
been, apparently, driven out, like a hernial sac, between the peri- 
toneum and the parietes, and projects into the abdominal cavity.” 
(Loe. cit. p. 566.) 
In Rhea “ the anterior and posterior intermediate and the posterior 
air-sacs are almost precisely similar to those of the Duck. The 
dorsal end of the dissepiment between the posterior intermediate and 
the posterior sac slopes backward; and the posterior wall of the 
latter has been, as Prof. Huxley describes it, ‘ apparently driven out 
like a hernial sac, between the peritoneum and the parietes’ projecting 
almost to the posterior end of the abdomen.” (Parker, loc. cit.) 
In Casuarius uniappendiculatus the anterior and posterior inter- 
mediate air-sacs are of about the same size and are separated from each 
other and from the posterior sac by erect, almost vertical dissepiments, 
which are entirely parallel with each other ; the dissepiment which 
separates the posterior air-sac from the one in front does not slope 
backwards any more than does the dissepiment in front of it. The 
posterior air-sac is entirely shut off from the abdominal cavity by 
the oblique septum ; there was no trace whatever of any prolongation 
of its walls among the coils of the intestines ; the whole of the sac, 
as in Apteryz, is enclosed between the oblique septum and the 
* P.Z.S. 1882, p. 560. ? P. Z. 8. 1883, p. 141. 
