MUSCULAR SYSTEM 



617 



phastidie, Indicatoridae, Bucconid&, Capitonidss and Galbulidse. The 

 fourth toe being turned backwards behaves like a hallux and 

 receives a tendon from the flex, hallucis, but this cannot be the only 

 reason, since the Cuculidse and Psittad are also zygodactyl, but 

 possess an ambiens, and belong to type I. 



VII. Tendons A and P are entirely disconnected, owing to the 



iv iii ii 



DIAGRAMS SHEWING ARRANGEMENT OF TENDONS OF THE FOOT. 

 A, Tendon of the anterior portion (m. flexor perforans). P, Tendon of the posterior portion (m. 



flexor hallucis. The toes are numbered i. ii. iii. iv. 



I-VIII, The types numbered according to Garrod, Gadow and Fiirbringer. I, Gallus ; II, 

 Apteryx ; III, Falconidae ; IV, Rhea ; V a , Cypselus ; Vb, Momotus ; V<=, Trochilus ; Vd, 

 Upupa and Irrisor ; VI, Picus ; VII, Oscines ; VIII, Harpactes duvauceli ; IX, Dacelo gigas ; 

 X, Heliornis surinamensis ; XI, Pandion ; XII, Cuculi. 



(Vc, VIII, IX, after preparations in Mus. E. Coll. Surg. ; X, after Beddard.) 



loss of the vinculum. Tendon A goes to ii. iii. and iv. ; Tendon 

 P only to the hallux, which is always well developed and the only 

 posterior toe. This type is the most differentiated and also the 

 simplest. Morphologically therefore it is the highest. It exists in 

 all the Passeres, except Eurylxmidse, and in some Herodii. 



