OF THE GREAT AUK, OR GARFOWL. 327 



part of its proximal end a strong compressed process, which is perforated, and which 

 developes the articular cavity for the inner condyle of the scapula, and is attached by 

 a short ligament to the end of the furculum : the main continuation of the body of the 

 bone supplies the rest of the joint for the scapula, with the major part of that for the 

 humerus, and then arches forward as a strong process to abut against the articular 

 surface of the clavicle (furcular prong), situated upon the upper and outer part of that 

 bone, about 6 lines from the extremity, which is ligamentously connected with the 

 scapula and inner part of the clavicular process of the coracoid. Tlie body of the 

 coracoid is, as usual, straight and inclined from the sternum upward, forward, and 

 slightly outward, losing breadth, gaining thickness, and assuming the trihedral form as 

 it rises. 



The clavicle (PI. LI. fig. 1, 58), anterior to the coracoid articulation, becomes com- 

 pressed, curves with a strong convexity forward, and then bends inward and backward, 

 thickening and expanding to become confluent with its fellow, in the ibrm of an inverted 

 but somewhat narrow arch (PI. LII. fig. 3). The length of each half of the so-formed 

 furculum, following the curve, is 4 inches 6 lines ; a short convex ridge is developed 

 from the point of confluence, which does not reach the anterior apex of the sternal keel. 



The humerus (PI. LI. fig. 1, 53 ; PL LII. figs. 8, 9, 10), 4 inches 2 lines in length, 

 is much expanded at the proximal end (PI. LII. fig. 8), where it measures 1 inch 

 across : the shaft is compressed, measuring 6 lines in long diameter, and only 2| lines 

 in short diameter, midway between the two ends (as in the outline above the fig. 9). 



The articular head (a) is a semioval convexity, 8 lines by 4| lines, overhanging the 

 concavity (d) on the anconal side, with the long axis extending from the radial {b) to 

 the ulnar (c) side, and with the ends continued upon the beginning of the radial and 

 ulnar (c') crests, of which the former is upper, the latter lower, in the natural position 

 of the bone. The radial crest or tuber is directly continued, contracting, into the 

 pectoral ridge. The ulnar crest is prominent, subtriangular, convex pal mad, concave 

 anconad, and sending off" on this surface a thick ridge {d) which divides the concavity 

 into a proximal depression (d), and a deeper distal one (e), into which an air-cell has 

 entered, but without pushing itself into the interior of the bone. From near the radial 

 end of the articular convexity, a thick ridge or raised rough surface (/) extends about 

 8 lines down the bone ; it gives insertion, by a well-marked narrow elliptical depression, 

 to the second pectoral muscle, the raiser of the wing. Below this ridge the convexity 

 of the shaft rapidly subsides into the almost flattened outer or radial surface. The 

 opposite surface at the proximal end of the shaft is concave, but becomes slightly 

 convex, transversely, down the rest of the shaft. The borders bounding the flattened 

 shaft, of which the radial one is formed chiefly by the pectoral ridge, describe very 

 slight sigmoid curves. The pectoral ridge is long and low, much less developed than 

 in birds of flight. A short ridge (PI. LII. fig. 9, g), abruptly rising from the end of 

 the radial border, extends to the middle of the distal anconal side of the radial condyle. 



