172 THE MYOLOGY OF THE RAVEN. 



In Geococcyx calif or nianus the ambiens is con- 

 spicuously developed. 



It arises from the apex of the prominent prepubic 

 spine of the pelvis, and the fibres passing directly down 

 to the inner side of the femur, and parallel with that 

 bone, form a strong fusiform muscle. As it approaches 

 the patella it terminates in a small flattened tendon, 

 which, piercing the fascial envelope of the knee-joint 

 below the inferior apex of that sesamoid, passes round 

 the joint, to become finally lost to the outer side and 

 opposite the summit of the tibia, where some of its 

 tendinous fibres mersje with the fibres of origin of the 



o o 



flexor perforatus digitorum, or, at least, with one of its 

 divisions. 



The ambiens is overlain by the sartorius muscle, and 

 in the figure is brought into view only through the 

 aid of a small dissecting-hook and chain, which pull it 

 forwards in order that it may be better seen (see Fig. 

 64 bis). 



98. The vastus internus is a very distinct and well- 

 defined muscle in the Raven, as it is in a number of other 

 birds. 



Stringops) it tends to become obsolete after reaching the knee, 

 becoming lost in the capsule of the knee-joint. In all Passerine 

 birds, and some others, it is always absent " (Coll. Scientific Papers, 

 London, 1885, p. 195). 



Several centuries ago Aldrovandi in his writings called the ambiens 

 muscle the m. tertius tibice ; it was the m. quindecimus femoris of 

 Steno, and the le crural grele of Vicq d'Azyr. Blasius, as well 

 as Merrem, termed it the " Langer Beinmuskel," while it was the 

 gracilis of Wiedemann, Tiedemann, Owen, Gurlt, Gegenbaur, De 

 Man, Selenka, Quennerstedt, Watson, and JSTeander. Cuvier and 

 Meckel had long French and German names for it respectively, and 

 it would seem that it received its present accepted name of the 

 ambiens from Sundervall in 1855. 



