334 PROFESSOR OWEN ON THE SKELETON 



The radius and ulna are of equal size in the Penguin, are much compressed, straight, 

 and leaving a mere linear interosseous space. The shaft is solid'. The ulnar carpal 

 bone projects as a flattened triangular plate from that side of the wrist, and simulates 

 by its distal extension a metacarpal bone. The radial (index) metacarpal is feebly 

 indicated by a low ridge from the proximal half of that border of the mid metacarpal — 

 this is broad and flat ; the narrower but similarly shaped " fourth " metacarpal coalesces, 

 as usual, by both ends with the third ; each of these supports a proximal phalanx, which 

 is pointed in the " fourth " ; that of the mid digit supports a second phalanx, also com- 

 pressed and pointed. The " hand " in the Penguin is longer than the humerus ; in the 

 Garfowl it is shorter. 



The iliac bones in the Penguin are remarkable for their divergence as they advance 

 from the acetabula, and for their convergence anteriorly ; they describe a sigmoid 

 curve, and are flattened horizontally : the sacrum is more expanded, and more abruptly 

 so anterior to the acetabula. The crest of the sacrum is more developed throughout 

 its whole length in the Penguin. The more extensive co-ossification of ilium and 

 ischium reduces the ischiadic foramen to a much smaller relative size than in 

 the Garfowl. The obturator foramen is continuous with the linear interval between 

 the ischium and slender pubis, and this is much shorter relatively than in the Gar- 

 fowl, extending scarcely as much beyond the ischium as this does beyond the ilium. 



The femur of the Penguin is thicker in proportion to its length. The rotular process 

 of the tibia is shorter ; the hollow between the pro- and ecto-cnemial crests is deeper ; 

 the patella is relatively larger. The anterior distal tendinous groove is bridged over by 

 bone. The ridge on the tibial side of the back part of the distal trochlea is more pro- 

 duced in the Penguin. But the most marked distinction in the bones of the leg of the 

 Penguin is the shortness, breadth, and persistent amount of distinctness of the three 

 confluent metatarsals. The toes are also relatively shorter and thicker ; and there is a 

 rudiment of a hallux or inner toe^, which is entirely wanting in Alca impennis. 



The result of this comparison is to show that the Urinatores of Blyth (Orr's 

 Cuvier's ' Animal Kingdom,' 8vo, 1840, p. 267) is an artificial group, and that the 

 wingless sea-bird of the southern region is of a family distinct from that to which the 

 wingless sea-bird of the north belonged : but we have not yet found among the winged 

 ea-fowl of the south any that manifest so close an affinity with Aptenodytes antarcticus 

 as many of the northern winged sea-fowl show to Alca impennis. To speculate upon 

 the derivative origin of either bird would be more agreeable than useful or really 

 instructive. 



Since the foregoing pages were in type, I have been favoured by Samuel Laing, Esq., 



' Catalogue of Osteology, vol. i. p. 219, no. 1137. ' 



" Descriptive Catalogue of the Osteology, Mus. Coll. Surg. vol. v. p. 216, no. 1117. 



