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Show 148 SEXUAL SELECTION : BIRDS. PAIU II. the other parts (see fig. 5G), and this fo1lows from the lower black mark of the elliptic ornament (b) having been originally thicker than the upper mark (c). Every ::;top can be followed in the process of confluence and modification; and the black ring which surrounds the ball of the ocellus is unquestionably formed by the union and modification of the three black marks, b, c, d, of the elliptic ornament. The irregular zigzag black marks between the successive oce1li (see again fig. 56) are plainly due to the breaking up of the somewhat more regular but similar marks between the elliptic orna-ments. 'fhe successive steps in the shading or' the ball-and-socket ocelli can be followed out with equal clearness. 'fhe brown, orange, and pale-leaden narrow zones which border the lower black mark of the elliptic ornament ean be seen gradually to become more and more softened and shaded into each other, with the upper lighter part towards the left-hand corner rendered still lighter, so as to become almost white. But even in the most perfect ball-and-socket ocelli a slight difference in the tints, though not in the shading, between the upper and lower parts of the ball can be perceived (as was before especially noticed), the line of separation being oblique, in the same direction with the bright coloured shades of the elliptic ornaments. Thus almost every minute uetail in the shape and colouring of the bnll-and-socket ocelli can be shewn to follow from gradual changes in the elliptic ornaments; and the development of the latter can be traced by equally small steps from the union of two almost simple spots, the lower one (fig. 57) having some dull fulvous shading on the upper side. The extremities of the longer secondary feathers which bear the perfect ball-and-socket ocelli are peculiar] y ornamented. (Fig. 59.) The oblique longitudinal CIIAl'. XIV. GRADATION OF CHARACTERS. HD stripes suddenly cease upwards and become confused and above this limit the whole upper end of the feathe;. (a) is c?vered wit.h white dots, surrounded by littlo black rmgs, stanchng on a dark ground. Even the oblique stripe belonging to the uppermost ocellus (b) is represented only by a very short irregular black mark with the usual, curved, transverse base. As this stripe is thus abruptly cut off above, we can understand, fi·om what has gone before, how it is that the upper thickened part of the ring is absent in the uppermost ocellus; for, as before stated, this thickened part is apparently formed by a broken prolongation of the next higher spot in the same row. ] rom the absence of the upper and thickened part of the ring, the uppermost ocellus, though perfect in all other respects, appears as if its top Ihta d beelnd ob1l iqube ly sliced oft: :Fig. 59. Portion ncar summit of one of WOU , t ink, perplex the Secondary wing-feathers, bearing any one, who believes that perfect ball-and-socket ocelli. a. Ornamented upper part. the plumage of the Arguspheasant was created as we now see it, to account for the imperfect condition of the b. Uppc•most, imperfect ball·and-socket ocellus. (The shading above lhe white mark on tho summit of the ocellus I~ here a little too dark.) c. Perfect ocellus. u~permost ocelli. I should add that in the secondary wmg-feather farthest from the body all the ocelli are |