61 



The anterior extremities are short and small. The scapula is 3 

 inches in length and 2 in its greatest breadth : its spine is feeble 

 and but slightly elevated. The humerus is 3 inches in length : and 

 is stouter and less laterally compressed than that of a common Otter 

 of the same longitudinal dimensions. The ulna and radius are stout, 

 and are separated from each other by a greater interval than in the 

 common Otter. The i)aws are remarkable for their diminutive size. 

 In the common Otter, from the extremity of the radius to the nail of 

 the last phalanx of the third finger the measurement is 3 inches ; in 

 the Enhydra it is 2^. 



The pelvis is long and narrow, measuring from the crest of the 

 ilium to the tuber ischii 6 inches : in the common Otter, the measure- 

 ment is but 4. The iliac bones are remarkably thick and solid, and 

 turnout from the spinal column. The distance from the centre of 

 the acetabulum to the crest of the ilium is 3 inches ; the breadth of 

 the ilimn \\. 



It is in the posterior limbs that the great power of the Enhydra 

 appears to be developed. The os femoris is short but very thick, 

 and its trochanter is bold and prominent : the trochanter minor is 

 small. The head of the femur is globular, and is destitute of the 

 ligamentum teres, as in the Seals : in the Otter this ligament exists 

 as usual. The length of the thigh bone from the great trochanter 

 to the condyles is 34- inches. Both the tibia and fibula are large 

 and of great comparative length : in the common Otter, they do not 

 exceed the femur; but here they exceed it by more than an inch, 

 the measurement being 4-^ inches. 



It is in the hind paws or paddles, Mr. Martin remarks, that the 

 greatest difference exists between the Otter and the Enhydra. They 

 are here admirably constructed as organs of aquatic progression. 

 Their length from the os calcis to the last phalanx of the outer toe 

 is 74- inches; and as the toes are long and connected by intervening 

 webs they form broad efficient oars. The toes graduate regularly 

 from the inner toe, which is the shortest, to the outer or fifth toe, 

 which is the longest. The metatarsal bone of the inner toe measures 

 14- inch, the toe analogous to the thumb and composed of only two 

 phalanges measures the same — the other toes have three phalanges 

 as usual ; the metatarsal bone of the fifth toe measures 2-i- inches ; 

 the toe itself 3 inches. The breadth of the foot, measured obliquely 

 across from the end of the metatarsal bone of the first toe to that 

 of the fifth is 2 inches. 



The nails of the fore paws are small and sharp ; those of the pad- 

 dles are blunt, but curved. 



The OS penis is a stout bone 3-| inches in length. 



Mr. Martin concluded by remarking that as the hinder extremi- 

 ties are jilaced far backwards, and when stretched out in the act of 

 swimming exceed the tail, this organ will appear placed between 

 them, almost as much as it is in the Seals ; between which animals 

 and the Otters the Enhydra forms, in his estimation, a palpable link 



