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Show 1905.] OSTEOLOGY OF THE EURYL/EMID.E. 53 Though I looked carefully for this slip, I failed to find it, yet I examined three or four specimens. Forbes showed that, in the matter of the syrinx, the Eurylaemidae agree most nearly with the Philepittidfe of the Old World ; and, after that, with the Cotingidae, Pipridae, and Tyrannidae of the New World. This organ is of the " Mesomyodian," " tracheo-bronchial " type, or, to adopt Gadow's term, the syrinx is tracheo-bronchial and " Anisomyodean." Had the syrinx instead of the plantar tendons been adopted as the basis of classification for this group, then the Cotingidae would have been regarded as the more primitive group, inasmuch as in Lipaugus cineraceus the intrinsic muscle, according to Beddard, is of great width, " which seems to foreshadow its division in the Oscines into a complex of muscles . . . ." The many characters which the Eurylaemidae and Cotingidae share in common-skeletal, muscular, syringeal, pterylological, Aic.-are surely proofs that these two groups are much more nearly allied than is generally supposed to-day : the likenesses are too many and distinct to be put down to convergence or correlated variation. The fact that the spina externa of the sternum is simple is generally bracketed together with the plantar tendons, and other characters, so as to emphasise the primitive character of the Eurylaemidae. But this same peculiarity of the sternum occurs again in the Cotingidae. The pterylosis of the Eurylaemida? is generally regarded as peculiar : as a matter of fact, it is hard to distinguish from that of the Cotingidae. The syndactyle foot again turns up-in the Cotingidae. We have already described the close resemblances which obtain in the skulls of these two groups. Turning now to the muscular system. The syringeal muscles Ave have already referred to. They offer no striking peculiarities of structure. Indeed, the only muscles which seem to call for comment in this summary are the brevis and longus divisions of the deltoideus. The separation of this muscle into two distinct parts is nowhere so complete as in the Passeres. In its primitive (archicentric) condition, this muscle arises, in part from the acromion and inner face of the expanded free end of the clavicle and in part from the os humero-scapulare and crista lateralis of the humerus. It is inserted by a common tendon into the base of the ectepicondyloid process ; the tendon forming the terminal of a practically homogeneous muscle. I have not yet had time to study the apocentricities of this muscle, but it would appear that as specialisation proceeds it breaks up into two more or less equal and perfectly distinct muscles terminating in a common tendon : later the brevis portion becomes suppressed and the longus much shortened, each receding farther and farther up the shaft of the humerus. I have only just realised the potentialities of this muscle as a factor in systematic work, and therefore have no large series of |