296 PROF. OWEN ON THE ANATOMY 
Galline in the absence of acrop. With respect to the cecal appendages of the intestine, 
though generally long in the Galline, they are subject to great variety in both the Stru- 
thious and Grallatorial orders: their extreme length and complicated structure in the 
Ostrich and Rhea form a peculiarity only met with in these birds. In the Cassowary, on 
the other hand, the ceca are described by the French academicians as entirely absent. 
Cuvier' speaks of ‘‘ un cecum unique” in the Emeu. In my dissections of these Struthious 
birds I have always found the two normal ceca present, but small ; in the Hmeu measuring 
from three to five inches long, and half an inch in diameter’ ; in the Cassowary measuring 
about four inches in length. The presence of two moderately developed ceca in the 
Apteryx affords therefore no indication of its recession from the Struthious type: these 
ceca correspond in their condition, as they do in the other Struthious birds, with the 
nature of the nutriment of the species. It is dependent on this circumstance also, that 
in the grallatorial bird (Ibis), which the Apteryx most resembles in the structure of its 
beak, and consequently in the nature of its food, the ceca have nearly the same relative 
size ; but as regards the Galle, taken as an order, no one condition of the ceca can be 
predicated as characteristic of them. In most they are very small; in many single. 
What evidence, it may next be asked, does the generative system afford of the affi- 
nities of the Apteryx? A single, well-developed, inferiorly grooved, subspiral intromittent 
organ attests unequivocally its relations to the Struthious group ; and this structure, with 
the modifications of the plumage of the respiratory organs and of the skeleton, lead to 
the same conclusion as that at which Mr. Yarrell® and myself had arrived’, from a study 
of the external organization of the Apteryz, viz. that it must rank as a genus of the 
cursorial or Struthious order. In deviating from the type of this order the Apteryx ma- 
nifests a tendency in the structure of the feet to the Galline, and in the form of the 
beak, to the Gralle ; but it cannot, without violation of its natural affinities, be classed 
with either. 
' Lecons d Anat. Comp. 1836. iv. p. 291. 
* The accurate Fremery speaks of “ ceca intestina duos pollices tantum longa, dimidium lata,” in the Emeu 
dissected by him, loc. cit. p. 76. 
> Loe. cit., p. 72. + Art. Aves, Cycl. of Anat. and Phys., i. 1836, p. 269. 
