272 



Transactions. — Zoology. 



bone ; of these four tendons one is a broken portion (fig. 2, g), a second is 

 twisted much out of position, and its fibres unravelled (fig. 2, A), the other two 

 are quite entire (fig. 2, i). 



They can easily be divided into two sets — a posterior or superficial pair, 

 and an anterior or deep pair. 



And this is best seen where they are enclosed in an aponeurotic sheath 

 just above and behind the tarso-phalangeal joint. 



The above aponeurotic sheath being divided into two main canals, one 

 anterior to the other, each containing two tendons, those lying in the posterior 

 canal are the tendons of the flexor perforatus digitorum (fig. 2, g, h), those 

 in anterior canal being the deep flexor tendons (i) (flexor perforans digitorum 

 pedis), but in both cases only to the third and fourth toes. 



The superficial and deep flexors to second toe will be separately described. 



Between the deep flexors and the posterior surface of middle trochlea a 

 sesamoid cartilage* is interposed ; from the sides of this cartilage springs the 

 aponeurotic archway, which has been before mentioned ; the septum between 

 the two divisions of this archway is thick and semi-cartilaginous. 



The flexor tendons after being conducted by this aponeurotic sheath beyond 

 the tarso-phalangeal joints, break up and run to their respective attachments. 



The greater part of tendons of flexor perforatus end in lateral slips to the 

 bases of proximal segments of third and fourth toes ; there are second 

 ^perforated tendons to the outer and third toe, those to latter toe being 

 broken across. 



The two tendons of flexor perforans respectively to the third and fourth 

 toes each subdivides into four slender slips, which have that flattened character 

 and imbricate relations to one another peculiar to digital tendons ; the 

 termination of those to outer toe is indistinct, except that the two deepest 

 seem to unite and become attached to base of ungual segment, while the two 

 superficial ones go to base of third segment of outer toe. The deep flexors of 

 third toe are broken across opposite second phalangeal joint. 



The inferior portions of the capsular ligaments of the phalangeal joints 

 are strengthened and grooved for the passage of these tendons. 

 Inner or Second Toe : — 



The proximal phalanx of this toe was the only part left, it was quite 

 loose and it has to be retained in situ by artificial means ; its external lateral 

 ligament, however, is present. 



To its base there still remain attached several tendons, and a portion of 

 the annular ligament retains others. 



It is quite clear that the superficial and deep flexoi's to this toe did pass 

 through a separate and distinct aponeurotic sheath to that of the third and 



* Same has been seen in ostrich. Loc. cit., p. 361. 



