130 THE OSTEOLOGY AND MYOLOGY 



of which they are inserted. The tendon of the middle toe often splits, to give off a slip 

 to the second toe, which is thus doubly supplied. 



E.ctensor communis dlgltorum brevis s. accessorius. — (Fig. 33, k, only the tendons 

 shown.) As already intimated, this muscle, which in anthropotomy is found upon the dor- 

 sum of the foot, is here carried up the leg ; only the pollical fiisciculus being left upon the 

 instep. It belongs to the fibular group. It is a diminutive muscle that arises from the 

 upper part of the fibula for an inch or so below the head of the bone, more or less blended 

 with the extensor longus poUicis, and covered by the peronei. In its whole course it lies 

 close to the fibula, passes behind the external malleolus, and then immediately splits into 

 three tendons, that pass to the second, third and fourth toes. These tendons are extremely 

 attenuated, and run very obliquely across the instep, beneath the tendons of the preceding. 

 Each runs along the fibular side of a toe, to be inserted into the base of the second (middle) 

 phalanx. As the tendon that goes to the fourth toe passes the fifth metatarsal, it gives off 

 a delicate slip to the little toe, which then has two extensor tendons besides its own from 

 the peroneus tertius. 



Extensor brevis poUlcls. — (Fig. 33, i.) This detached remnant of the preceding, as it 

 seems to be, though not lying upon the leg, may be most conveniently noticed in this con- 

 nection. It is the only muscle upon the dorsum of the foot ; it is devoted exclusively to 

 the great toe, hut occasionally gives off a little thread-like tendon to the second toe. It is 

 a diminutive, fleshy fasciculus, lying diagonally across the instep from the external malleo- 

 lus ; its delicate tendon runs to the base of the distal phalanx of the great toe, alongside 

 the tendon of the extensor longus pollicis. 



Peroneus tertius, s. extensor minimi digiti. — (Fig. 33, /".) While the third peroneus of 

 anthropotomy is sometimes wanting, and at best is little more than a part of the long com- 

 mon digital extensor, passing with the latter over the front of the ankle to reach the base 

 of the fifth metatarsal, it is here found well developed, and in what appears to be its real 

 character as a member of the fibular group, and the proper extensor of the little toe. 

 Although small, it is a perfectly distinct muscle, arising from the head of the fibula, over- 

 laid by the peroneus longus. The fleshy jjart is about an inch long, and forms a flattened 

 spindle. The very long and exceedingly delicate tendon passes along the fibula, behind 

 the external malleolus, along the external border of the foot, to be inserted into the base 

 of the ungual phalanx of the little toe. It has also some attachment to the base of the 

 little toe, but none to the fifth metatarsal.^ 



Peroneus secundus s. brevis. — (Fig. 33, e.) Very slender, fusiform, muscular for rather 

 more than half its length, arising in common with the long digital extensor, distinct from, 



'.\natom!sts differ as to the homolojjy of the three muscles inserted into a digital phalanx, the other three blending with 



last descrlbeil. If the fasciculus upon the dorsum of the the correspoufling tendons of the lon<; extensor before inser- 



foot be recognized as the whole of a rudimentary extensor tion; and that, in the present example of the opossum, the 



digitorum communis brevis s. accessorius, the one above de- fasciculus in question does really, at times, if not ordinarily, 



scribed under this name should rather be regarded as the send another tendon to the second toe, thus allowing the 



peroneus tertius; and the extensor minimi digiti as a dis- inference that sometimes the third and fourth tendons may 



tinct m\iscle from the latter. Among other things that seem be developed. Should the muscle be found with these four 



to favor this view (independently of the fact that actual tendons, its homology would be plainer. Moreover, even 



dislocation of the parts of a morphologically simple muscle the third peroneal of man, despite its metatars;d insertion, 



is rare, and therefore improbable in any given seeming in- appears to partake more of the character of a digital exten- 



stance), it may be stated that the extensor brevis of man sor, and may bo therefore an undeveloped condition of the 



only gives one tendon (that of the great toe) to be actually same muscle that is above described as the short or accessory 



