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Show 1874.] MR. GARROD ON THE ANATOMY OF THE COLUMBA. 249 1. On some Points in the Anatomy of the Columba. By A. H . G A R R O D , B.A., Fellow of St. John's College, Cambridge ; Prosector to the Society. [Keceived March 19, 1874.] In the present communication it is not my intention to describe in detail the anatomy of any single kind of Pigeon, because that can be, most of it, learnt from the dissection of any common species; but, from the opportunities which are presented to m e in the performance of m y prosectorial duties, it will be m y endeavour to point out those peculiarities which I have been able to recognize in the soft parts of the large number of generic forms of the Columbae that have passed through m y hands. It is m y hope that those naturalists who have opportunities of examining genera and species which it has not been m y good fortune to obtain, will record their observations, not omitting those points on which I shall endeavour to lay stress on the present occasion. That there is not a perfect constancy in the pterylosis and visceral anatomy of the Pigeons has been known for some time. Nitzsch, in his work on Pterylography, incidentally mentions that in the genus Goura there are no caeca to the intestine, and that the gall-bladder is absent. The same facts are noted by Hunter*. The former naturalist also refers to the absence of the oil-gland in the same genus. Prof. Owen saysf that the gall-bladder is constantly deficient- a statement which, as will be seen further on, requires some qualification. The fact that all the European species of Doves belong to the genera Columba, Turtur, and Pterocles has caused zoologists to estimate the characters of the whole suborder more from these than from the much larger number found in extra-European countries; and the results arrived at from a more extended study tend considerably to modify the prevailing impression as to the constancy of certain characters. The differences observable in the following structures have engaged my attention:- 1. The number of rectrices. 2. The presence or absence of the oil-gland, which is never otherwise than nude. 3. The presence or absence of caeca to the intestine, which in no genera, except in Pterocles and Syrrhaptes, exceed half an inch in length. 4. The presence or absence of the ambiens muscle, which does not seem as yet to have engaged the attention of naturalists, so far as this suborder of birds is concerned. I. The number of tail-feathers in the different genera of the Columbae. Nitzsch divides the Pigeons into those with 12 and those with * Essays and Observations, vol. ii. p. 291. t Anatomy of Vertebrates, vol. ii. p. 177. PROC. ZOOL. Soc-1874, No. XVII. 17 |