of the nutriment of the species. It is dependent on this circum- 

 stance 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 caca have nearly the same relative size ; but 

 as regards the Grallce, taken as an order, no one condition of the 

 ceEca can be predicated as characteristic of them. In most they are 

 very small ; in many single. 



" What evidence, we next ask, does the generative system afford of 

 the affinities of the Apteryx ? A single, well-developed, inferiorly 

 grooved, subspiraL intromittent organ attests unequivocally its rela- 

 tions to the struthious group; and this structure, with the modifi- 

 cations of the plumage, and the peculiarities of the skeleton, lead me 

 to the same conclusion at which I formerly arrived*, from a study 

 of the external organization of the Apteryx, viz. that it must rank as 

 a genus of the cursorial or struthious order ; and that in deviating 

 from the type of this order it manifests a tendency in one direction, 

 as in the feet, to the gallinaceous order ; and in another, as in the 

 beak, to the Grallte ; but that it cannot, without violation of its na- 

 tural affinities, be classed with either." 



A living specimen of the Gymnotus electricus, from the Amazon, 

 was exhibited by Mr. Porter. 



August 28th, 1838. 

 No meeting took place. 



• Art. Aves, Cycl. of Anat. and Phys., i. 1836, p. 269. 



