THE MUSCLES OF THE LOWER EXTREMITY. 235 



anterior digits alone are flexed ; but when the flexor 

 longus hallucis is put in action, the digits as well as 

 the hallux are simultaneously flexed " (Coll. Memoirs, 

 p. 291). No such vinculum exists in the Eaven, and 

 in this particular it agrees with the Passeres and 

 Upupa epops. Further studies in this direction will 

 be very acceptable. 



A few years ago I published the following remarks in 

 reference to the variations to be seen in the arrano^ement 

 of these plantar tendons, and the uses that could be made 

 of them in avian taxonomy (124 of Bibliography). I 

 said that " both Professor C. J. Sundevall and Professor 

 Garrod have paid considerable attention to the dis- 

 position of these tendons in the feet of birds. If I 

 mistake not, the first-named author was the writer who 

 originally invited attention to the fact that the tendon 

 of the flexor longus hallucis was completely independent 

 of the tendon of the flexor perforans digitorum pjro- 

 fundus in the Passeres ; and in view of this fact he 

 grouped these birds together, and as the Hoopoe {Upupa) 

 exhibited the same condition, he included that form with 

 them. Garrod pushed the matter much further, however, 

 and made some very extensive dissections upon the deep 

 plantar tendons in a great many different orders of birds. 



" Irrespective of the plan of the foot, in all birds, in so 

 far as its digits are concerned, there are two muscles 

 present in the leg, which, arising from the tibia and 

 fibula, send each a tendon to the toes a,^ flexors : these 

 muscles are the flexor longus hallucis and the flexor 

 perfoi^ans digitorum profundus. In passing through or 

 over the hypotarsus of the tarso-metatarsus, at the back 

 of the ankle-joint, the tendon of iho, flexor longus hal- 

 lucis is either superflcial or external to the tendon of the 

 other flexor mentioned. 



