OCR Text |
Show 644 MR. GARROD ON CERTAIN MUSCLES OF BIRDS. [June 17, terminal fibres of this muscle are situated external or superficial the accessory semitendinosus. After this muscle has been removed or turned back, there is seen a deeper muscle, which, if the one described above did not exist, would be justly considered to be the true femoro-caudal and the accessory femoro-caudal, part springing from the iliac ridge and part from the coccyx, whilst both are inserted into the posterior portion of the linea aspera and have the nerve to the semimembranosus situated between them and the adductor magnus. The semimembranosus is also peculiar in having a second head of origin from the ischium, behind the femoro caudal, and just in front of the origin of the semitendinosus, so that the femoro-caudal runs partly in a separate canal between the two heads of origin of this muscle and covered by it. The other muscles are present as in most birds. The ambiens is strong. Species examined. Apteryx owenni. Apteryx mantelli. In Casuarius the postacetabular portion of the tensor fasciae is very large, and is overlapped below and behind by the semitendinosus near its origin ; the femoro-caudal forms a small cylindroidal belly, which is continued upwards as a narrow tendon ; the accessory femoro-caudal is enormous, being perforated by the sciatic artery and nerve ; it replaces to a great extent the obturator externus, which is peculiarly small and situated anterior to it in origin, as usual. The semitendinosus is present and has a broad accessory head. The ambiens is absent. The other muscles are as in most birds. Species examined. Casuarius bennettii. Casuarius bicarunculatus. galeatus. In Dromceus novee-hollandice the semitendinosus is larger than in Casuarius, and the accessory head is large ; the femoro-caudal is absent ; and the accessory femoro-caudal is very large, being pierced by the sciatic artery and nerve. The biceps cruris is very peculiar in not being inserted in its usual characteristic manner, but ending a little anterior to the middle of the thigh very indefinitely, blending with the fasciae in that region, and not being continued directly to the fibula at all. The semimembranosus also is peculiar in having an aponeurotic connexion with the middle of the linea aspera, from about the middle of its course. The ambiens is absent. In Rhea americana a somewhat similar condition is found. The biceps is normal; and the semitendinosus, the accessory semitendinosus, as well as the postacetabular portion of the tensor fasciae are much as in Casuarius and Dromceus. The femoro-caudal is absent; the accessory femoro-caudal is large, being perforated by the sciatic artery and nerve ; and the ambiens is strong. In Struthio camelus the ambiens is also well developed. |