STRUTHIONES 



507 



which are the outward expression of a reticulate internal 

 ■structure, like a ruminant's stomach. Towards the extremity 

 of the caecum the folds cease to he so definitely arranged in 

 a network, and some to present an indication of a spiral dis- 

 position. Bhea has also very large caeca, and there are 

 traces of the spiral valve of the ostrich. The caeca of the 

 cassowaries and the emu, as will be seen from the table of 

 measurement, are very much smaller than those of the 

 ostrich and Bhea. Gadow mentions an obscure formation of 



Fig. 235.— Sybinx of Apteryx Fig. 236.— The same, feom behind. 



MantelU. Feont View. 

 (After Forbes.) 



o.oOf in ttis and following 

 figs., tracheal rings. 



an internal network by the presence of folds which may be 

 compared with the structure of the cseca of Galodromas, 

 already referred to. The caeca of Apteryx are long and nar- 

 row, like those of the tinamous (excluding Galodromas). 



Struthio has the most remarkable Hver of all the Stru- 

 thiones. The two lobes are intimately fused into one heart- 

 shaped lobe. There is an indication of a spigeHan lobe, as 

 vdth other StrutMones, and the single bile duct (there is no 

 gall bladder) opens, exceptionally, only 4 cm. from the 

 pylorus. Bhea has, as a rule, no gall bladder, but Gadow 

 found traces of one in a specimen dissected. This occurred 

 (see figs. 19, 20, p. 34) both in Bh.Darwini and Bh. americana. 

 Casuarius and Dromaus have a well-developed gall .bladder. 



