210 THE VOYAGE OF H.M.S. CHALLENGER. 



In their descriptions of Trichcchus Dr. Murie and Professor Cunningham differ. The former 

 states that it arises by a long narrow belly, by a tendon from the extra bone outside the cuneiform, 

 and is fleshy three-quarters the length of the hallucial metacarpal, being inserted by tendon and 

 fascia over the metacarpophalangeal joint ; the latter that it arises from a sesamoid bone which 

 slides upon the tibial side of the internal cuneiform, and is inserted into the inner side of the base 

 of the 1st phalanx of the hallux. Murie writes that it is fleshy, and Cunningham that it is 

 tendinous, which he considers is probably owing to his specimen being a pup ; and although Murie 

 explains that this muscle in the Seal is entirely tendinous, I found muscular fibres in Phoca. 



The Abductor tertius quinti digiti in Phoca vitulina is exposed after reflecting the tendinous 

 structure concealing it. Murie has classed it as the 2nd head of the abductor ossis metacarpi 

 quinti. It arises from the adjacent sides of the bases of the 4th and 5th metatarsal bones, and 

 the tendinous structure covering these phalanges ; after crossing the 5th metatarsal it is inserted 

 into the fibular side of the head of this bone. 



In Arctocephalus it is 1 inch long, with no fibres, and arises from the fascia completing the tunnel 

 for the peroneus longus tendon. This origin is a small round tendon at right angles to the plantar 

 surface. It is inserted into the tendon of origin of the abductor ossis metatarsi quinti. In Otaria 

 it is one of the heads of origin of the abductor ossis metatarsi quinti. 



In Trichcchus (Murie) it is also named the abductor ossis metatarsi quinti. Its origin is the 

 same as in Arctocepihcdus and Otaria, but the insertion is into the base of the 5th metatarsal bone. 

 In Trichcchus (Cunningham) the origin and insertion are similar to the former. 



The Abductor minimi digiti in Phoca vitulina arises between the proximal ends of the 3rd and 

 4th metatarsal bones, and crosses obliquely outwards to the tibial proximal plantar side of the 1st 

 phalanx of the 5th digit. In Arctocephalus it has two bellies. The first arises from the dorsal half 

 of the plantar surface of the os calcis by muscular fibres, and extends longitudinally from the 

 insertion of the gastrocnemius to the posterior tendon of this bone. The second belly arises from 

 the base of the 5th metatarsal bone. The first belly is inserted, after forming a flat tendon, into 

 the base of the 5th metatarsal beneath the second belly, which goes to the dorsal distal end of 

 the 5th metatarsal, and is inserted into the outer or dorsal side of the flexor brevis minimi digiti. 

 Murie's description of this muscle in Otaria differs from the above. 



In Trichcchus Murie states that it comes from the outside of the os calcis and not from the 

 plantar fascia, while Cunningham says that it arises from the fascia covering the outer surface of 

 the abductor ossis metatarsi minimi digiti, and is inserted into the outer side of the base of the 

 1st phalanx of the minimus. 



The Abductor ossis metatarsi quinti in Arctocephalus is the flexor brevis minimi digiti (Murie), 

 and the abductor ossis metatarsi minimi digiti (Cunningham). It is a small muscle, and arises 

 from the os calcis to the outer side of the origin of the abductor minimi digiti by a slender 

 elongated tendinous slip, which is closely united with the muscle just mentioned, and lies along its 

 fibular edge. It is inserted into the distal fibular side of the 5th metatarsal to the fibular side of 

 the abductor. 



In Otaria the origin is double ; the outer head is the same as described above ; the inner I 

 regard as the 3rd abductor of the 5th digit which is found in Phoca. In Trichcchus (Cunningham) 

 it exhibits the usual attachments, but Murie gives a different description. 



