| OCR Text |
Show 626 MR. P. CHALMERS MITCHELL ON THE [June 16, presence or absence of the ambiens muscle as of primary importance. H e divided birds into the Homalogonatae, which possess the muscle, and the Anomalogonatae, in which it is absent. Here and there among groups which certainly must be associated with the Homalogonatous birds there are instauces in which the ambiens is absent, and in which Garrod believed the ambiens to have been present, but recently lost. It is of great interest therefore to Fig. 4. Leg-muscles of Opisthocomus cristatus showing yestigial ambiens. Glut. 2, Attachment of gluteus medius. Glut. 3, Attachment of gluteus tertius. Glut, ant., Gluteus anterior. II. 2. Flexor perforans et perforatus indicis. III. 2, Flexor perforans et perforatus medii. Per. 2, Peroneus secundus. I. Flexor longus hallucis. II. Flexor perforatus indicis. III. Flexor perforatus medii. IV. Flexor perforatus quarti. find a species different individuals of which show so great variations in the condition of the ambiens muscle, reaching from the normal complete condition found by Garrod to the extremely vestigial condition in the specimen from which fig. 4 was drawn. Some time ago, in a paper communicated to this Society , I recorded the discovery of vestiges of the ambiens in the case of two 1 " On the Perforated Flexor Muscles in some Birds," P. Z. S. 1894, p. 495. |
