REPORT ON THE SEALS. 205 



longus hallucis, the plantaris giving a shp apart from the usual tendons to the distal end of the 5th 

 metatarsal. 



The Plantar fascia in the Phocinte is formed out of the tendons of the gracilis, semimembranosus, 

 and semitendinosus, which are prolonged into the foot, while the tendon of the plantaris muscle is 

 interposed between it and the combined tendon of the flexor, and does not form a plantar fascia, 

 but strengthens the common tendon, and forms part of the flexors of the digits. In the 

 foot three layers are got from this modification, the first by the gracilis, &c, the second by the 

 plantaris, and the third by the flexor longus hallucis and flexor longus digitorum. 



The Lumbricalcs in the Phocinfe and Macrorhinus may be represented by the anterior tendons 

 from the combined tendon going into the sheath of the digits. 



The Lumbrical muscles in Arctocephalus gazclla are five in number. The first lies between the 

 long flexor tendons for the 1st and 2nd digits, coming out of the ventral main division. It arises 

 from the adjacent sides of these tendons and forms a small tendinous slip, which is inserted into 

 the distal dorsal side of the 1st metatarsal. The second arises from the surface and ventral side 

 of the long flexor tendon for the 3rd digit, and is inserted by muscular fibres into the tunnel in the 

 superficial flexor tendon formed out of the plantaris muscle. The third arises from the surface of 

 the deep tendon for the 4th digit, and ends upon it near the distal end of the 4th metatarsal bone, 

 like the last. The fourth arises from the dorsal side of the deep tendon for the 4th digit, passes 

 beneath the deep tendon for the 5th digit, and is inserted by a small tendon into the ventral side of 

 the distal end of the 5th metatarsal. The fifth comes from the tendon of a different muscle. The 

 superficial tendon for the 5th digit from the plantaris gives origin upon its surface to a lumbrical 

 muscle, which ends on the same tendon lower down. From the description of these slender 

 fusiform muscular slips it will be seen that there are five, four from the combined tendons of the 

 flexor longus digitorum and the flexor longus hallucis, and the fifth from the plantaris tendon. In 

 Otaria there are six, the sixth is derived from the outermost tendon of the flexor longus digitorum, 

 but there are no other differences. 



The Accessorius is the M. caro-quadrata of' Lucae. In Phoca vitulina, Phoca hispida, and 

 Phoca barbata it is a triangular muscle, with its base directed outwards, and arises from the dorsal 

 surface and posteiior end of the os calcis to the inner side of the groove for the long peroneal 

 tendon. The fibres pass inwards and obliquely backwards over the dorsal border of the hindward 

 corner of this bone, forming a fine tendon which is inserted into the outer side of the tendon 

 of the plantaris, before this muscle reaches the combined tendon. In Macrorhinus leoninus it 

 was wanting, but most probably had decayed. In Trichechus it is absent, and was not noticed in 

 Otaria. 



The Tibialis posticus in the Phocinse and in Macrorhinus leoninus is triangular, and lies to the 

 outer side of the flexor longus digitorum. It arises from the inner side of the interosseous mem- 

 brane, from the anterior two-thirds of the inner surface of the tibia, from the anterior third of the 

 ventral edge of the fibula near the interosseous membrane, and from the inner side of the dorsal 

 tuberosity of the tibia beneath the place of fusion of the tibia and fibula. It forms a strong 

 tendon which passes beneath the flexor longus digitorum on its ventral side, and enters the ventral 

 division of the groove on the outer surface of the distal extremity of the tibia. 



In Phoca, near the tubercle of the scaphoid, it gives off a slip which becomes the middle slip of 

 the abductor hallucis ; to the inner side of the abductor slip it gives off another in which the 



