[303] 'The Pigeon Book,' by Mr. B. P. Brent, 1859, p. 41.
[304] 'Die Staarhälsige Taube, Das Ganze, &c.,' s. 21, tab. i. fig. 4.
[305] 'A Treatise on the Almond Tumbler,' by J. M. Eaton, 1852, p. 8, et passim.
[306] A Treatise, &c, p. 10.
[307] Boitard and Corbié, 'Les Pigeons,' &c. 1824, p. 173.
[308] 'Le Pigeon Voyageur Belge,' 1865, p. 87.
[309] Prof. A. Newton ('Proc. Zoolog. Soc.' 1865, p. 716) remarks that he knows no species which presents any remarkable sexual distinction; but it is stated ('Naturalist's Library, Birds,' vol. ix. p. 117) that the excrescence at the base of the beak in the Carpophaga oceanica is sexual: this, if correct, is an interesting point of analogy with the male Carrier, which has the wattle at the base of its beak so much more developed than in the female. Mr. Wallace informs me that in the sub-family of the Treronidæ the sexes often differ in vividness of colour.
[310] I am not sure that I have designated the different kinds of vertebræ correctly: but I observe that different anatomists follow in this respect different rules, and, as I use the same terms in the comparison of all the skeletons, this, I hope, will not signify.
[311] J. M. Eaton's Treatise, edit. 1858, p. 78.
[312] In an analogous, but converse, manner, certain natural groups of the Columbidæ, from being more terrestrial in their habits than other allied groups, have larger feet. See Prince Bonaparte's 'Coup-d'œil sur l'Ordre des Pigeons.'