1888.] NATURAL SCIENCES OF PHILADELPHIA. 153 



flexor longus digitorum and flexor longus hallucis. Its muscular 

 fibres are restricted to the side of the foot, all that portion on the 

 sole being tendinous. 



Lumhricales four, a.s usual ; the one inserting in the fifth digit 

 rises from the 4th deep tendon. 



Rising from the 5th deep flexor tendon, beside the lumbricals, is a 

 simihir but somewhat longer belly, whicli blends with the 5th flexor 

 brevis tendon. This seems to correspond to what Mivart describes 

 as " accessorius " in the third and fourth digits of the cat.^ The cat, 

 however, has a distinct accessorius similar to the one in the present 

 specimen. 



In the plantar layer of adductores we have adductor hallucis, ad. 

 indicis, and ad. minimi digiti, which rise in common from the bases 

 of the 2nd and 3rd metatarsals and are united for a third of the way 

 out towards the phalanges. The adductor minimi digiti soon di- 

 vides into two heads, of which the outer inserts into the inner side 

 of the distal end of the 5th metatarsal, constituting the opponens 

 minimi digiti. The other head again divides into two slips, of which 

 the more distal becomes the normal adductor, while the more prox- 

 imal runs around to blend with the extensor system at the metatarso- 

 phalangeal joint. 



The intermediate and dorsal systems are fused, as in the hand, 

 and terminate in a similar maimer. Flexor brevis slips appear to 

 be given to each side ot each digit ; the flexor brevis hallucis rises by 

 a number of small heads from the cuneiform and ligaments at the 

 base of the hallux. 



In the dorsal sj'stem there is a slender abductor ossis metatarsi 

 minimi digiti, from the postero-external part of the plantar surface 

 of the calcaneum to the tuberosity at the root of the 5th metatarsal, 

 and a stout abductor minimi digiti, which was much cut on both 

 sides by the skinning. 



The " long tendons " described in the hand appear on both sides 

 of each digit except the 1st and 5th. There is none on the outer 

 side of the 5th, its place being taken by the regular abductor, and 

 there appeared to be no representative on the tibial side of the hallux 

 in either foot, though the mutilation of that region in the skinning 

 might have destroyed it. That on the fibular side of the hallux in- 



' I have recently seen a cat which lacked the connecting muscles in the third 

 and fourth digits and possessed one on the fifth, thus repeating the structure shown 

 here in the polar bear. 



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