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Show 352 MR. R. S. WRAY ON THE MORPHOLOGY [Apr. 5, t. mediae, T.Md, but scantily represented on the manus. There is part of a row, T.Mn, representing the minores, and a few rows of marginals, M. The dorsal surface of the humerus is uniformly covered by rows of feathers. The pollex bears four remiges and a few coverts, Al. The disposition with regard to tbe bones gives 16 primaries or metacarpo-digitals, and about 20 (20-22 or 23) cubitals. The quills have not the same firm attachment as those of the Carinates, there being no grooves in the phalanges to receive them, and their bases project beyond tbe anterior edge of the bone (cf. fig. 2, p. 351). In the Carinatse the quills attached to the phalanges lie almost parallel to them, whereas here the angle is little larger than a right angle. This is a much more primitive condition. The primaries are disposed as follows :-Eight metacarpals, one addigital, four middigitals, and three predigitals. This probably represents a more primitive wing-form than the Carinate, where seven metacarpals and five digitals is the highest number of primaries. Probably the ancestral wing-form became modified into the forms we know by reduction and specialization of these feathers, seen more numerous in the Ostrich than elsewhere. The Rhea's wing presents the same general characters as the Ostrich ; the ventral surface is bare, and the dorsal surface, with the feathers cut, shows the same arrangement; but when the relations of the remiges to the bones are considered, it is seen to approach more nearly to the Carinate type in some respects. The primaries are twelve in number, there being seven metacarpals, one addigital, two middigitals, and two predigitals. This reduction is correlated with shortening and reduction of the manus. The angle of insertion of the digitals is more obtuse than in the Ostrich. The wing of the E m u I have not had the opportunity of dissecting, but it is probably similar in arrangement to the Ostrich and Rhea, judging from a stuffed specimen. The wing of the Cassoway1 shows a great exaggeration of the feature, noticed in the Ostrich, of the quills projecting beyond the bones, its quill-spines being the sole remains of the cubital remiges. The Apteryx shows, as was first pointed out by Prof. Flower (Roy. Instit. Lect. 1886), a few true cubital remiges, indicated by their long quills. The Penguin's Wing. This departs the most of all wings from the general plan. The paddle form of the wing and its scale-like feathers are familiar, and there is little or no differentiation apparent beyond the passage from mere scales anteriorly to feathers posteriorly. On the ventral side 1 In the wing of a Cassowary dissected since writing tbe above there are to be seen structures representing, in all probability, the " primaries," which appear at first sight to be entirely wanting in these forms. I hope to describe this specimen, together with some other interesting Ratite wings, in a future paper. |
