1881.] ANATOMY OF THE ERINACEIDvE. 397 



fore, is enclosed in a sling formed l)y the two divisions of this 

 muscle. 



The soleeus is well developed, but arises by a short tendon from 

 the head of the fibula only. Extensor hnllucis longus, from the 

 middle of the tibia beneath the large tiOialis posticus, is very small ; 

 l)ut the ejctensor dxgitovuia longus, whicli arises by a tendon from 

 the external condyle of the femur, is moderately developed. The 

 peronei muscles arise together from the head of the fibula, but 

 divide at once into tlie />. brevis, longus, and quinti digiti ; tiie 

 tendons of the latter are inserted into the distal phalanges of the 

 fourth and fifth toes respectively. 



The plantaris is well developed, arising by two heads from the 

 external condyle. Its tendon becomes at the heel superficial to that 

 of the tendo Achillis, over the insertion of which it glides, and, 

 j)assing into the sole of the foot, gives origin altogether to the jle.vor 

 digitorvm brevis, and becomes connected with the plantar fascia. 

 The Jiexor digitorum longus and Jlexor hallucis longus are insepa- 

 rably united. 



The tibialis jjosticus is represented by (wo separate muscles, one 

 having its origin from the tibia, the other from the fibula, and which 

 may therefore be described as the internal and external divisions of 

 this muscle. The latter, the tibialis jwsticus externus, is very 

 slender ; arising from the head of the fibula internally, it forms 

 a long and slender tendon, which, passing down on the inner side 

 of the tibia with the tendon of the external division, is inserted 

 into the scaphoid bone. The internal division, tibialis posticus 

 internus, is much larger ; arising from the head of the tibia, and 

 from half the length of the bone by a fascial aponeurosis, it forms 

 also a long tendon, which extends along the side of the foot between 

 the integument and the plantar fascia, and, spreading out, is inserted 

 round the base of the central callosity of the integument. 



It is remarkable that the first described of these muscles has tiie 

 insertion usually observed in the tibialis jiosticus of other mammals, 

 while the latter has the origin of that muscle, but not its insertion. 

 The action of this latter muscle is evidently to fix the central cal- 

 losity of the sole of the foot, and so assist progression on smooth or 

 inclined surfaces. 



Flexor digitorum brevis arises, as above desori!)ed, from the tendon 

 of the plantaris, and is not connected with the os calcis ; it divides 

 into five flat tendons, which form the perforated tendons for the five 

 toes, ^he Jlexor accessorius is well developed ; arising from behind 

 the prominent bony tubercle on the os calcis which supports the 

 tendon of the peroneus longus, it is inserted obliquely into the 

 outer side of the jlexor digitorum longus tendon, opposite the base 

 of the fifth metatarsal bone. There are, as in the manus, four lum- 

 bricales for the four outer toes, and with similar attachments. 



The palate is marked by eleven ridges, all simple and undivided ; 

 the first corresponds to the space between the first and second in- 

 cisors, the second to the canines and first premolars, the third to 

 the second premolars, the fourth to the third premolars. The ton- 



