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Show 1881.] ANATOMY OF THE ERINACEIDSE. 397 fore, is enclosed in a sling formed by the two divisions of this muscle. The solaius is well developed, but arises by a short tendon from the head of the fibula only. Extensor hallucis longus, from the middle of the tibia beneath the large tibialis posticus, is very small; but the extensor digitorum longus, which 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 the p. brevis, longus, and quinti digiti; the 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, passing into the sole of the foot, gives origin altogether to the flexor digitorum brevis, and becomes connected with the plantar fascia. The flexor digitorum longus and flexor hallucis longus are inseparably united. The tibialis posticus is represented by two 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 posticus 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 m u c h 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 the insertion usually observed in the tibialis posticus 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 callosity of the sole of the foot, and so assist progression on smooth or inclined surfaces. Flexor digitorum brevis arises, as above described, 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. The flexor 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 flexor 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 incisors, the second to the canines and first premolars, the third to the second premolars, the fourth to the third premolars. The ton- |