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Show 348 MR. R. S. WRAY ON THE MORPHOLOGY [Apr. 5, Storks, where seven occur. The predigitals are the only other remiges of the manus which show modifications of any interest. In the typical condition (cf. Plate X X X I . fig. a) we have the large pre-digital 2 (a) and the small remicle (/3), with their dorsal and ventral coverts all intimately attached to the phalanx. This arrangement is probably generally present in the Pygopodes, Gaviae, Tubinares, many Limicolae, Pterocles, Odontoglossae, Herodiones, Anseres, Pelicans, Striges, and Accipitres. Among other birds it is probably not generally present, but it may be found in many of the lower forms of Passeres, and in some Picarise, probably never in Gallinse. The remicle disappears in these forms, but its dorsal covert remains well developed, especially well seen in the Gallinse, and its ventral covert may also remain, but often disappears. All trace of the group may disappear, as in the nine-primaried Passerines, where predigital 2 is reduced to a mere rudiment, but can generally be detected : its covert is always well marked. The so-called pencil-feather of the Woodcock is the dorsal covert of the remicle group. The chief, most interesting, and most puzzling modification of the cubital feathers is that in a great many birds the fifth remex is always undeveloped, its coverts being normally developed and present. This occurs probably in all birds except Phcenicopterus, Gallinse, Passeres, and a few Picarlse. Up to the present I have never met with a trace of this feather in a vestigial condition. If the figures of the preparation of the distal part of the cubitus of the Golden Eagle be compared with those of the Pheasant (see p. 346), the exact nature of this modification is at once apparent. In the Pheasant (a, a') the fifth remex is present with its coverts, showing all normal relations; in the Golden Eagle (b, b') the coverts are present but no remex. The former condition may be termed quincubital, the latter aquin-cubital. Such is the constancy of one or the other condition in each natural group, that I have as yet met with no exceptions anywhere, except among the so-called Picarise, many of which are, and most of which probably will turn out to be, quincubital. The Goatsuckers are aquincubital, while the Swifts are quincubital. Pterocles is aquincubital; Goura is aquincubital. Of course exceptions may turn up, seeing that of the whole number of birds but a comparatively few have as yet been tested for this point. In the Gallinse the first cubital feather is shortened ; this is possibly due to mechanical requirements in the folding of the wing, as the metacarpal remiges are inserted so near the actual joint as to leave but little room. Nitzsch states that sometimes the last feather on the manus undergoes shortening. I have not met with this condition. In the description of the Duck's wing it was pointed out that the upper major covert to the first metacarpal remex is very small and rudimentary. When the feathers are all plucked off except the remiges, major and median coverts, the appearance at the wrist-joint is that represented in the figs. 6-9 (Plate XXXII.), where the remiges are red, the major coverts yellow, and the median blue. The diagram above each of the figures shows the real homologies of these |