24 Descriptions of Preparations. 



whilst it lias an unanchylosed metatarsal which is unrepresented 

 in the fore-limb_, and which carries a hallux consisting of two 

 phalangesj and in having a medius digit with four phalanges, 

 and a fourth or ' annularis ' digit with five^ which latter is not 

 represented at all in the bird's fore-limb^ but corresponds to the 

 similarly constituted ' annularis ' of the Lacertilia. In the tarso- 

 metatarsus two foramina are seen to pass through from before 

 backwards a little below its proximal double articular head, showing 

 its essentially triple composition. At the same end and on the 

 posterior aspect of the bone^ a bony canal passes along the outside 

 of the base of the entocalcaneal process for the lodgment of the 

 tendon of the flexor perforans digitorum ; and at the distal end 

 of the bone, a little above the external intertrochlear notch, we 

 see another bony canal for the tendon of the adductor annularis. 

 The posterior unanchylosed metatarsal bone has, in Pigeons as 

 ordinarily in perching birds, its distal articular facet at such a 

 level as to put the inferior or plantar surface of the inner or hind 

 toe on to a level with that of the other three. 



For the points in which the skull of the Pigeon contrasts with that 

 of the gallinaceous birds, see Description of next Prei^aration ; 

 and for many other points in the comparative anatomy of 

 the Columbidae, the Rasores, and the extinct Dodo, see 

 Strickland and Melville, The Dodo and its Kindred, 1848, 

 pp. 44, 71, et passim. See also Alphonse Milne -Edwards, 

 Sur I'Osteologie du Dronte, Ann. Sci. Nat. Ser. v. tom. v. 

 1866, p. 355; Professor Owen, Transactions of the Zoological 

 Society, vol. vi. pt. 2, 1867. A description of the tarso-meta- 

 tarsus and the posterior or inner metatarsus, with a specifica- 

 tion of the very slight differences which exist between them 

 and those of Columba Livia, is given by Professor Melville in 

 the Avork on the Dodo just referred to, pp. 100-109. 

 For the Osteology of the Gallinaceous and Pigeon Tribes generally, 

 see the very valuable paper by W. K. Parker, Zoological 

 Transactions, v. pt. 3, 1864; the views put forth in which 

 have been adopted to a considerable extent in this descrij)- 

 tion. 

 For the Osteology of the skull, see the paper by the same author, 

 Phil. Trans., 1866, and Professor Huxley's Lectures, pp. 

 69-129. 



