18 
The pneumatic fossa is much deeper, but does not extend into the shaft; the two 
olecranial grooves are relatively narrower, and restricted to the posterior inferior angle 
of the lamelliform shaft; a sesamoid in the extensor tendon plays upon each, The 
articular surfaces for the radius-and ulna are feeble convexities upon almost the same 
transverse line, and the joint scarcely allows of the movements of flexion and extension. 
In the Alca impennis it is adapted for much freer motions. 
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 
' Catalogue of Osteology, vol. i. p. 219, no. 1137. 
* Descriptive Catalogue of the Osteology, Mus. Coll. Surg. vol. v. p. 216, no. 1117, 
