OCR Text |
Show inserted to tlie femur along a narrow vertical line. In T anellus the caudal portion is very large, whilst the accessory portion is present, but minute and with a tendinous degeneration similar to that just described. In Thinocorus, Hydrophasianus, and Rhynchcea both portions are present and large. In Glareola, Charadrius, and Himantopus the caudal portion is large, and the iliac is extremely minute, represented by not more than a few fibres. In Gallinago and Scolopax the caudal portion is of moderate size, the iliac portion completely absent. 166 DR. P. CHALMERS MITCHELL ON THE [May 16, Thigh-muscles of Chionis alba. Eight thigh, external view. IL.TR.E., P., M., A. llio-trochanterici externus, posterior, medius et anterior. IL.FIB. (1). Origin of ilio-fibularis seu biceps, cut and reflected. IL.FIB. (2). Insertion of biceps, cut and reflected. I.F. Iscliio-femoralis, seu obdurator externus. CAUD.IL.F. 1 ,2. Insertions of caud-ilio-femoralis (accessory femoro-caudal (1) and femoro-caudal (2)). CAUD.IL.FL. Caud-ilio-flexorius, cut, and origin reflected. IS.FL. Ischio-flexorius. P.I.F. Pub-ischio-femorales, seu adductores longus et magnus. The tendinous areas are dotted. X. Tendinous area on accessory femoro-caudal. F.T.E. Femoro-tibialis externus. CEdicnemus in this respect, as in others, shows its wide divergence from the typical Limicoline condition. Of the others, Thinocorus, Hydrophasianus, and Rhynchcea show what is probably the archecentric or generalised condition for birds, the presence of both muscles in a well-marked form. The remaining birds of the list show that the tendency of modification in the group is for the disappearance of the iliac portion (the " accessory" of Garrod); and complete disappearance has been reached by Gallinago and Scolopax, two birds in other respects relatively highly specialised. Caud-ilio-Jlexorius (Semitendinos'its and Accessory semitendi-nosus), Ischio-flexorius (text-fig. 28).-In all these birds the three |