196 THE VOYAGE OF H.M.S. CHALLENGEE. 



distal end of the 5th metatarsal. These four tendons go backwards over the metatarso-phalangeal 

 joints, expand upon the outer surfaces of the 1st phalanges of the four digits, and are inserted into 

 the distal ends of the 1st phalanges of these digits, into the outer surfaces of the ligaments between 

 the phalanges, and into the proximal ends of the 2nd phalanges. 



In ArctocepJialus gazella it is a long narrow muscle, and arises from the external condyle of the 

 femur, by a small fasciculus posterior to the insertion of the gluteus maximus, which passes back- 

 wards over the capsule of the knee-joint, gaining fibres from it, from the outer sides of the 

 head of the tibia and fibula adjoining the fused tibio-fibular articulation, also from the anterior 

 half of the outer border of the fibula by a fine but strong aponeurosis ventral to and touching the 

 tendon of origin of the peroneus brevis from the same border. Anterior to the malleolus it is a 

 strong tendon, which passes beneath the annular ligament, traverses the shallow groove on the 

 outer surface of the fibula, and the groove on the astragalus, lies on the outer surface of the tarsus 

 between the cuboid and cuneiform bones, and expands and divides into four slips over the bones of 

 the 3rd and 4th metatarsals. The first or ventral runs along the dorsal side of the 2nd metatarsal ; 

 the second along the middle of the 3rd metatarsal, the third along the ventral side of the 4th meta- 

 tarsal. The fourth crosses the outer surface of the middle of the 4th metatarsal, and runs down the 

 ventral side of the 5th metatarsal. At the metatarso-phalangeal articulation, the tendons begin 

 gradually to widen ; over the distal ends of the proximal phalanges they completely cover their 

 outer surfaces; and after passing over the joints and sharing in the formation of the posterior 

 ligament they are inserted into the proximal ends of the 2nd phalanges of the 2nd, 3rd, 4th, and 

 5th digits ; from their attachments, fine aponeurotic sheets are prolonged onwards, and end 

 imnoticeably over the phalanges. In the Phochife I did not find any origin from the femur, as 

 described by Lucae. In Otaria and Trichcchus there is no tibial origin. In the Phocinse, Macror- 

 hinus, and ArctocepJialus it extends the digits, and flexes the ankle. In the Phoenue it is supplied 

 by the musculo-cutaneous nerve (ventral division). 



The Fibular Eegion in all the specimens has the same muscles. The peronei longus, quinti 

 digiti, and brevis. 



The Peroneus longus, the peroneus primus of Lucae, in the Phocinre and Macrorhinus is a longi- 

 tudinal band of fibres. It arises from the small pit on the external condyle of the femur above 

 the depression for the origin of the popliteus, from which it is separated by the intervention of the 

 capsule of the knee-joint, which is attached to the femur between these two origins, and above it is 

 the termination of the insertion of the gluteus maximus; also from the external surface of the capsule 

 of the knee, from the outer surface of the fused tibio-fibular articulation, slightly from the adjacent 

 surfaces of both bones and from the fascia above the muscle. It courses backwards over the 

 tibio-fibular ankylosis, and lies in the hollow between the bones of the leg. About the junction 

 of the middle with the posterior third of the fibula it ends in a strong tendon, which leaves the 

 interosseous space and crosses obliquely backwards and upwards to gain the inferior groove on 

 the outer surface of the fibula, then it follows the bed of this groove, which runs to the dorsal 

 malleolus beneath the annular ligament. It passes over the tendons of the peronei brevis and 

 quinti digiti which lie on the calcaneo-astragaloid articulation, and, entering the dorsal groove on 

 the posterior outer corner of the os calcis, runs obliquely backwards, inwards, and downwards in the 

 groove upon the dorsi-plantar surface of the cuboid bone. It goes beneath the ligament stretching 



