OCR Text |
Show 134. DOMESTIC PIGEONS. CHAP. v. often destroy our definitions. Forms which may be called " aberraut" must owotimos be included within groups to which they do not accurat 1 y belong. Characters of all kinds must be used; but as with birds in a state of nature, those afforded by the beak are tho best and roost readily appreciated. It is not possible to weigh the importance of all tho characters which have to be used so as to make the groups and sub-groups of equal value. Lastly, a group may contain only ( ne race, and another and loss distinctly defined group may contain several races and sub-races, and in this case it is difficult, as in the classification of natural species, to avoid placing too high a value on characters which are common to a large number of forms. In roy measurements I have never trusted to the eye; and when speaking of a part being large or small, I always refer to tho wild rock-pigeon (Columba livia) as the standard of comparison. 'rhe measurements are given in decimals of an inch.5 I will now givo a brief description of all the principal breech:;, Tho following diagram may aid the reader in learning their names and seeing their affinities. The rock-pigeon, or Columba livia (including under this name two or three closoly-alli cl ub-spocies or geographical races, hereafter to be described), may be confidently viewed, as we shall see in the no:x.t chapter, as the common parent-form. The names in italics on the .righthand side of tho table show us the most distinct breeds, or those which have undergone the greatest amount of modification. Tho leno-ths of the dotted lines rudely represe11t the degree of diAtinctness of each breed. fl-oro the parent-stock, and tho namoA 5 As I so often refer to tho size of tho C. livia, or rock-pigeon, it may be convenient to give the mean between tho measurements of two wild birds, kindly sent me by Dr. Edmondstono from the Shetland Islands:- Length from feathered base of beak to end of tail .. ,, , , to oil-gland .. from tip of bcoJr to end of tail .. of tail-fen, t h crs from tip to tip of wing .. , of folded wing . . . . . . Bcak.-Lougth from tip of beak to feathered base .. . . . . . . Thickness, m asurrd vmtically at further end of nostrils lnchcs. .. 14·25 9·5 . . 15·02 4·G2 . . 2G·75 , Breadth, measured at same place . . . . . . . . . . . . Foet.-Lcngth from end of middle too (without claw) to di~tal end of tibia 9·25 ·77 ·23 ·lG 2·77 , J"ength from end of middle toe to end of hind too (without claws) 2·02 Weight 14t ounrA)s. CHAl'. v. OESCIUPTION OF BREEDS. 1% Fig. 17·-Thc Rock-pigeon, or Columba Iivia.• The parent-form of all domesticated Pigcou ~ . cplloasc e1d under te'a ch other in tho columns show the . . 1 1 . mo1 e 01 cAs e y connoc mg mks. The distances of the dotted l. f'. each tb · . mcs 1om b o er approximately represent tho amount of difference etween the several breeds. • G Tbi~ drawing was made from a dead btrd. 'l'ho six following figures wore drawn with great care by 1\'fr. Luke Wells from living birds selected by 1\'Ir. Tcgctmcier. It may be confidently as ortcu that tho characters of the r;ix ~n· rrls which have hcen figured are not 111 tho least exaggcrat(•rl. |