OCR Text |
Show 284 MR. W. P. PYCRAFT ON THE [Mar. 17, lengths of the segments of the wing. Thus, in Scythrops, the brachium and antebrachium are of equal length, whilst the manus is only a very little less in length than either of these segments. The brachium is longer than the antebrachium, and the latter is in turn longer than the hand in Coua, Rhamphococcyx, Rhinococcyx, Eudynamys, Guira, and Crotophaga. The relative disproportion between the length of the brachium and ante-braeliium is especially marked in Dromococcyx and Piaya. The brachium is longer than the antebrachium, but the latter and the manus are equal in length in Centropus and Taccocoua. In Cuculus and Cacomantis the brachium and manus are subequal and shorter than the antebrachium. In Coccystes the antebrachium and manus are subequal and longer than the brachium. The variation in the length of the wing among the Cuculi becomes still more forcibly illustrated when compared with the hind limb, the difference apparently varying with the power of flight. In Cuculus, Coccyzus, and Cacomantis, for example, the wing is considerably longer than the leg. In Chrysococcyx the two limbs are subequal. In Geococcyx, Crotophaga, and Coua the wing is much shorter. Taking the combined length of the femur and tibio-tarsus of each species as a standard of measurement, it will be found that in Crotophaga the wing exceeds this length only by the distance from the middle of Ph. I. D. II. to the tip of the wing. In Geococcyx the wing is slightly less than the length of the standard. Coua has the shortest wing of all, it being about i- shorter than the combined length of femur and tibio-tarsus. In the Musophagi the brachium is somewhat longer than the antebrachium, but the latter is considerably longer than the manus. The ulna, as in the Cuculi, bears prominent bosses for the attachment of remiges. As in the Cuculi, the collum trochlecp is very conspicuous, giving the distal end of the humerus an obliquely truncated form. The coraco-humeral groove is wanting. The proximal border of the crista superior is very long and concave, the distal border short and convex. The ectepicondylar tubercle is very small. The Ph. of D. III. in the Cuculi sends outwards from its post-axial border a prominent spur, this is wanting in the Musophagi. ix . T he P elvic L im b . The pelvic limb in the Cuculiformes has, in common with the Psittaci and many Coraeiiformes, a zygodactyle pes. The hypo-tarsus is complex, and the tibio-tarsus has an ossified extensor bridge. In all save Geococcyx the limb is non-pneumatic, and in this genus only the femur is pneumatic. The pelvic limb of the Cuculiformes has the 2nd and 3rd trochleae nearly equal in length, but the latter is conspicuously larger in size. The third trochlea is placed comparatively high |