THE EXTREMITIES OF ORYCTEROPUS CAPENSIS. 597 



common flexor of the toes will be noticed under my description of the tibialis 

 posticus. 



Rapp describes, under the old name of" caro quadrata Svlvii," an accessory flexor as 

 present in Myrmecophaga tamnhdua 1 . According to the same authority, the hallux in 

 this animal has no special flexor, but shares with the other digits the tendinous supply 

 of the common flexor. 



Flexor brevis digitornm. — This muscle, as in the case of Dasypfts, was absent. 



Meckel observes 2 that it appears most correct to admit that t lie Edentata arc deprived 

 of a small flexor communis, and that that which is described as such represents the short 

 head of the perforating flexor, for the reason that the tendons of the former are not 

 perforated, and that the analogy with the anterior member militates in favour of this 



conclusion. 



Tibialis posticus. — This muscle took origin from the inner aspect of the head of the 

 fibula, and from the opposite-looking edge of the posterior portion of t lie tibia, and in 

 part from the interosseous membrane, the anterior tibial vessels pas-in^ between its 



fibular and tibial heads of origin. It is intimately connected, for nearly the whole of its 



length in the calf, with the flexor rfigitoi '/>/. A little above the inner n db-ilus it is 

 continued into two flat tendons, which pass under a strong ligamentous pulley or arch, 

 situated on the posterior aspect of the above process. 



The deeper of the two tendons, after passing under a strong internal lateral ligament 

 of the ankle, which separates it from its fellow, terminates at the posterior part of the 

 inferior ridge of the ento-cuneiform bone ("hinder part of scaphoid," according to Prof. 

 Humphry 3 ); while the more superficial, belonging to the fibular belly of the muscle, 

 divides into two branches, one of which joins by a broad expansion t lie tendon of the 

 common flexor, while the other terminates at the posterior part of the sesamoid ossicle 4 

 which lies alongside of the ento-cuneiform bone, and which is attached, by a ligament 

 proceeding from its anterior extremity, to the inner side of the base of the proximal 



phalanx of the hallux. 



Cuvier's representation of the termination of the last-named tendon is very clear 5 . 



The broad expansion of the first-mentioned branch of the superficial tendon had con- 

 nexions which are of interest, since they tend to show a ditferentiation, in an animal 

 belonoin"" to the Bruta, of a flexor longus Iwllucis from the common flexor muscle ; for, 

 posteriorly, it was continued tendinous into a muscular offset from a portion of the 

 common flexor which arose from the lower part of the fibula, while, anteriorly, it took 

 a laro'e, nay, almost a principal share in forming the flexor tendon of the hallux. 



An arrangement somewhat similar to that just described is occasionally met with in 

 Man according to Bichat 6 , in the tendon of the tibialis posticus, of which, besides its 

 usual prolongation to the ento-cuneiform bone, " souvent autre prolongement, qui est 

 externe, se poste sous la plante du pied, et se confond avec ses ligamens." 





Oj). cit. p. 315. 



« Op. cit. p. 50. ' OP- dt. P- 657. 3 Op. cit. p. 315. 



4 No mention whatever is made of this ossicle (which exists in Das>i r ns proportionally better developed) by Prof. 

 Humphry. According to Cuvier, « Ossemens Fossik-s,' he. cit. p. 136, « l*os surnumeraire du bord interne [of the 



....... • Av,„+ n nmr . »»1 OKR fir> « 



tocuneiform] 



An 



4 Anat. Comp. pi. 256. fig. 6. 



