REPORT ON THE SEALS. 203 



lowermost third of the tibia and the interosseous membrane. In the Phocinoe it is supplied by a 

 branch of the great sciatic nerve. 



The union and insertion of the tendons of the flexor longus hallucis, and the flexor longus 

 digitorum in the Phocinre is as follows : — The tendon of the flexor longus hallucis is the largest 

 in the sole ; on its tibial side, 1 inch posterior to the os calcis, the tendon of the flexor longus 

 digitorum unites with it. Upon its fibular aspect the plantaris tendon expands, and is fused 

 with it by its outer surface. A slip from the plantar fascia of the gracilis, &c, blends with it 

 along the dorsal edge ; opposite the proximal extremities of the metatarsals this union of tendons 

 and plantar fascia divides. The part which corresponds to the flexor longus digitorum gives off two 

 slips. The ventral slip descends to the distal end of the terminal phalanx of the hallux, and is 

 inserted there. The dorsal slip goes to the proximal dorsal side of the 1st phalanx of the hallux, 

 into which it is inserted. 



The rest of the tendons, which roughly are those of the flexor longus hallucis, break up in a 

 more complex manner. For the 2nd digit two tendons spring out of the common one. The anterior 

 is the superficial or perforated tendon, which gives off an anterior slip to blend with the sheath. 

 The anterior superficial tendon splits over the proximal end of the 1st phalanx, and is inserted into 

 the proximal end of the 2nd phalanx. The posterior or deep tendon gives off a posterior slip, which 

 is inserted into the distal end of the metatarsal ; then the deep tendon passes through the slit in the 

 superficial tendon, and is inserted into the distal end of the terminal phalanx of the 2nd digit. For 

 the 3rd digit there are three slips coming off separately. Two come off anterior and posterior to 

 each other. The third is a large, strong slip, springing from the main tendon between the flexor 

 tendons for the 3rd and 4th digits. This large slip is attached to the distal end of the 3rd meta- 

 tarsal. The anterior slip divides into an anterior and posterior part. The anterior is inserted into 

 the sheath, the other is the superficial tendon or posterior part, which is inserted like the other 

 superficial tendons. The posterior part from the main tendon passes through the same slit as the last, 

 and is inserted as in the former group. For the 4th digit, they are the same as for the 2nd digit, 

 with a slight difference. There is no posterior slip from the deep tendon, and the anterior slip to 

 the sheath is formed by the direct continuation of the plantaris tendon, which only fuses on its 

 under surface with the great tendon. Those for the 5th digit have the same attachments. The 

 difference in this group, as compared with the 2nd digit, is in the formation of the superficial or 

 perforated tendon, which is formed from the plantar fascia of the gracilis, &c, and only joins the 

 great tendon on its dorsal edge. This superficial slip gives off a small one to the distal end of the 

 metatarsal of the 5th digit. 



In Macrorhinus leoninus the combined tendon on the plantar surface divides into four slips. 

 The ventral or internal one soon breaks into three. The ventral and middle slips of these three 

 are for the hallux, and have the same course and insertion as in Phoca vitulina. The dorsal of 

 these three is for the 2nd digit and forms an anterior and posterior tendon, which are the same 

 as those for the 2nd digit of Phoca vitulina, without the posterior slip for the distal end of the 

 metatarsal. In the 3rd digit they are similar to those in Phoca vitulina, without a slip from the com- 

 bined tendon. In the 4th digit they are also similar to those in Phoca vitulina, but the plantaris 

 muscle forms a greater part of the tendons. In the 5th digit the tendon is chiefly formed by the 

 plantaris tendon and by the plantar fascia of the gracilis, &c. It comes off in one slip and divides 

 into two, which have the same insertion as in Phoca vitulina, but there is no slit in the superficial 



