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Show 164 DOMESTIC PIGEONS. CHAP. v. faced tumbler, (o) tho English carrier, and (D) tho Dagadotton carrier (of Noumoistor), all drawn of tho natnral size ~nd viewed laterally. In tho canior, besides tho elongation of tho bones ot the ~ace, the spa~o between the orbits is proportionally a little narrower than m tho rock-pigeon. In tho J3agadottcn tho 11ppcr mandible is remarkably arched, .and the promaxillary bones arc proportionally broader. In the short-faced tumbler tho skull is more globular; all tho bones of tho face are much shortened, and tho front of the skull and descending nasal bones arc almost perpendicular; tho maxillo-jugal arch and premaxillary bones form an al.mo~t straigl1t line; tho space between tho prominent edges of the cyc-orbtts m depressed. In tho barb tho premaxillary bonos ~ro much. shortened, and th •ir anterior portion is thicker than in tho rock-pigeon, as IS tho lower part of tho nasal bone. In two nuns the ascending brancbcg of tho promaxillarics, ncar their tips, wore somewhat attenuated, and in these biTds, as well ns in some others, for instance in tho spot, the occipital crest over the foramen wns considerably more prominent than in tho rock-pigeon. • In the lower jaw, tho articular surface is proportionally smaller in many breeds than in the rock-pigeon; and tho vertical diameter more cspocinlly of the outer part of the articular smfaco is considerably glwrtcr. May not this be accounted for by the lessoned u. o of the jaws, owing to nutritious food having been given during a long period to all highly improved pigeons? In runt., carriers, and barbs (rtnd in [t lesser degree in several breeds), tho whole side of the jaw ncrtr tho articular end is bent inwards in a hig!ly remarkable manner; and tho superior margin of tho ramus, beyond the middle, i rofl.cxcd in an equally romnrkablo manner, as may be Rccn in thu accompanying figures, in comparison with tho jaw of the rock-pigeon. c A .. ll f•'ig. 25.-Lowcr jaws, seen from above, of naturul size. .A. Rock-pigeon. B. Runt. C. Barb. This rofl.exion of tho upper margin of tho lower jaw is plainly connected with tho singularly wide gape of tho mouth, as has been described in runts, carriers, and barbs. Tho rcfl.oxion is well shown in fig. 26 of the head of a runt seen from above; here a wide open space may be observed on each side, between the edges of the lower jaw and of tho premaxillary C!IAP. v. OSTEOLOGICAL DIFFERENCES. 165 bonos. In tho rock-pigeon, and in several domestic bTeeds, the edges of the lower jaw on each side como close up to the premaxillary bones, so Fig. 26.-Skull of Runt, seen from above, of natural size, showing the rcftexcd margin of the distal portion of the lower jaw. c A Fig. 27.-Latcral view of Jaws, of natural size. A. Rock-pigeon. B. Short-faced Tumbler. C. Bagadotlen Carrier. that no open space is left. The degree of downward curvature of tho distal half of the lower jaw also differs to an extmordinary degreo in some breeds, as may be seen in the drawings (fig. A) of the rock-pigeon,"'(n) of the short-faced tumbler, and ( o) of the Bagadottcn carrier of Neumeister. In some runts the symphysis of the lower jaw is remarkably solid. No one would readily havo believed that jaws differing so greatly in the several above-specified points could have belonged to the same species. Ve1·tebrce.-All tho breeds have twelve cervical vertebrro.36 But in a Bussorah carrier from India, tho twelfth vertebra carried a small rib, a quarter of an inch in length, with a perfect double articulation. Tho dorsal vertebrce are always eight. In tho rock-pigeon all eight boar ribs ; tho eighth rib being very thin, and tho seventh having no process. In pouters all the ribs are extremely broad, and, in three out of foul' skeletons examined by me, tho eighth rib was twice or oven thrice as broad as in tho rock-pigeon; and the seventh pair had distinct processes. In many breeds there arc only seven ribs, as in seven out of eight skeletons of various tumblers, and in several skeletons of fantails, tUI'bits, and nuns. In all these breeds tho seventh pair was very small, and was destitute of processes, in which respect it differed from the same rib in tho rock-pigeon. In one tumbler, and in the Bussorah carrier, oven tho sixth pair had no process. The hypapophysis of the second dorsal vertebra varies much in development; being sometimes (as in several, but 36 I am not SUl'O tlmt I have designated tho different kinds ofvcrtobrre coiTectly; but I observe tlmt differ nt anatomists follow in this respect different rules, and, as I use tho same terms in tho comparison of all the skeletons, this, I hope, will not signify. |