Contributions to Bird-Anatomy and Classification. 9 



These will here be all considered seriatim ; they may all, 

 it may be mentioned, be well seen in the common Fowl. 



(1) The ambiens. — This muscle, unlike the others to be 

 subsequently mentioned, lies on the lower or inner surface 

 of the thigh. As generally developed, it is a more or less 

 slender fusiform muscle, which, arising from the prsepubic 

 spine or process of the pelvis, close in front of the acetabulum, 

 runs along the inner side of the thigh superficially, and then, 

 turning slightly outwards, runs, as a thin tendon, in the fibrous 

 tissues covering the knee-joint (in some cases perforating the 

 patella) to the outer side of the leg, and terminates there by 

 joining one of the tendons of the superficial flexor of the toes, 

 the flexor perforatus digitorum. The course of this muscle will 

 be made clear by the accompanying representation of it, as 



Fie?. 4. 



Thigh of Touraco ( Corythaix ej-ythrolophd) viewed from the inner side, 

 to show the ambiens muscle, arising from the praepubic spine of the 

 pelvis (P), and running along to blend with one of the tendons of 

 origin of the flexor perforatus digitorum (/. p). F, femur ; Pt, Pa- 

 tella ; I.C, inner condyle of femur ; T, tibia ; b, biceps (cut short) ; 

 s, sartorius (also cut); e,e, extensor femoris; sin, semimembranosus; 

 add, adductores. 



N.B. The surroimding parts have been somewhat distorted from their 

 natural positions to show better the course of the ambiens. 



seen in a Touraco {Corythaix erythrolopha). In one or two 

 cases (e. g. (Edicnemus, Stringops) it tends to become obso- 



