138 PROCEEDINGS OF THE ACADEMY OP 



type. The patella, however, is of immense size, and of an indes- 

 cribable, irregular shape. According to Owen, it develops from 

 two centres a matter interesting in connection with the presence 

 of two sesamoids in the elbow. The tibia is a bone about eight 

 inches long, and nearly cylindrical in its continuity. It closely 

 corresponds, in general, with the same bone of a loon, for example, 

 except that it does not develop the long apophysis above the 

 knee-joint. There is a considerable protuberance, however, above 

 the plane of the. articulation, formed by the extension of two sharp 

 cnemial ridges that meet above, defining a long deep fossa that lies 

 between them. The distal extremity offers nothing peculiar; the 

 osseous bridge for confinement of the flexor tendons is perfect, 

 and the trochlear surface has the usual configuration. The fibula 

 is six inches long, and extremely slender from above the middle 

 downwards. It abuts against the tibia at both ends, and also 

 for about an inch of its length at a place nearly half-way down. 

 Elsewhere, the interspace between the two bones is considerable. 



The ankle-joint has a peculiar free, persistent ossicle, about the 

 size and shape of a split pea. It appears to be a sesamoid, and it 

 lies on the posterior aspect of the joint ; but owing to an unfor- 

 tunate inadvertence in the preparation of the specimen, its exact 

 position and relations were not made out. 



The tarso-metatarsus (Fig. 8) is the most remarkable bone of 

 the skeleton in several respects, and the one more particularly 

 diagnostic of the family. Penguins afford probably the only in- 

 stances, among recent birds, of width crosswise being decidedly 

 greater than thickness antero-posteriorly, and more than half the 

 length; and the only case of persistence throughout life of fenes- 

 tra; marking the composition of the bone of three originally dis- 

 tinct metatarsals. In the present species, the bone is rather under 

 two inches long, from an inch to one inch and a third wide at 

 different points. The front shows two deep grooves lengthwise 

 from one end to the other, and in each of these grooves there is 

 an oval perforation, that would about admit the passage of a 

 goose-quill. Behind, the corresponding grooves are nearly obso- 

 lete. The proximal extremity is an uninterrupted articular sur- 

 face for the tibial condyles, the inner impression being much the 

 more strongly marked. The distal extremity is deeply cleft in 

 two places, the three metacarpal prongs being coinpleteby isolated. 

 The central one of these projects beyond the lateral ones. The 



