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angles of the manubrium. In the Dasyures, Opossums, Phalangers, 

 and Petaurists, the manubrium is compressed and elongated, and the 

 clavicles are joined to a process continued from its anterior extremity. 

 The small clavicles of the Kangaroo have a similar connection. 



" The cartilages of the true ribs, (which frequently become ossi- 

 fied in old Marsupials) are articulated as usual to the interspaces 

 of the sternal bones ; the lašt of these supports a broad flat cartilage. 

 " The clavicles are relatively strongest and longest in the burrowr- 

 ing Wombat, weakest and shortest in the Great Kangaroo. In the 

 latter they are simply curved \vith the convexity forwards, and mea- 

 sure only two inches in lensgjį. In the Wombat they are up\vards 

 of three inches in length, aiiff have a double curvature ; they are ex- 

 panded and obliquely truncate at the sternal extremity, where the 

 articular surface presents a remarkably deep notch : they become 

 compressed as they approach the acromion, to vi^hich they are at- 

 tached by an extended narrow articular surface. In the Koala the 

 clavicles are also very strong, but more compressed than in the 

 Wombat, bent out\vards in their whole extent, and the convex mar- 

 gin formed, not by a continuous curve, but by three almost straight 

 lines, vvith intervening angles, progressively diminishing in extent 

 to the outermost line which forras the articular suiface with the 

 acromion. In most of the other Marsujjials the clavicle is a simple 

 compressed elongated bone, with one general outward curvature. In 

 the genus Perameles there are no clavicles. 



" The scapula varies in form in the diiferent Marsupiata. In the 

 Petaurists it forms a scalene triangle, with the glenoid cavity at the 

 convergence of the two longest sides. In the "VVombat it presents a 

 remarkably regular oblong ąuadrate figure, the neck being produced 

 from the lower half of the anterior margin, and the outer surface 

 being traversed diagonally by the spine ; which, in this species, 

 gradually rises to a full inch above the plane of the scapula, and 

 termhiates in a long narrovv compressed acromion arching over the 

 neck to meet the clavicle. In the Koala, the superior costa does not 

 nin parallel with the inferior, but recedes from it as it advances for- 

 wards, and then passes down, forming an obtuse angle, and with a 

 gentie concave curvature to the neck of the scapula ; a small process 

 extends from the middle of this curvature. In the Potoroos the upper 

 costa is at first parallel vvith the lo\ver; but this parallel part ismuch 

 shorter ; the remainder describes a sigmoid flexure as it approaches 

 the neck of the scapula. In the Great Kangaroo, the Perameles, 

 Phalangers, Opossums and Dasyures, the \vhole upper costa of the 

 scapula describes a sigmoid curve, the convex posterior portion of 

 •which varies as to its degi'ce and extent. 



" The subscapular surface is remarkable in the Perameles for its 

 flatness ; but presents a shallow groove near the inferior costa. In 

 most other Marsupials it is more or less convex and undulating. 



" In the Great Kangaroo the svpraspinal fossa is of less ex- 

 tent than the space belo\v the spine, and the spine is inclined 

 upw'ards. In the Perameles and Dasyures the proportions of the 

 snpra and infra spinal surfaces are reversed, and the wliole spine 

 is bent do\vnM'ards over the in/rarpinal surface. In the Potoroos 



