MAY, 1921. AMERICAN MARSUPIAL, C^ENOLESTES OSGOOD. 93 



examined. It articulates principally with the outer lateral surface of the 

 cuneiform but also has slight contact with the ulna. 



The metacarpals are slender and rounded with somewhat expanded 

 heads and bases, the former slightly the larger. The medius is the 

 largest. The indicis and annularis are slightly shorter and of about 

 equal length. The pollicis is about three-fifths as long as the indicis 

 and the minimus is scarcely more than half as long as the annularis. 

 The first three are of approximately equal diameter, the annularis is very 

 slightly more slender, and the minimus is slightly broader. The outer 

 pairs are evenly and slightly divergent from the middle. The pha- 

 langes are regular in number and form. The basal ones of the second, 

 third and fourth fingers are nearly equal in length; that of the fifth 

 finger is slightly shorter, and that of the pollex is shortest. The claw 

 of the middle finger slightly exceeds the others. The claw of the 

 pollex reaches to the middle of the first phalanx of the index finger and 

 the claw of the fifth finger extends to the first phalangeal joint of the 

 fourth finger. The ungual phalanges of the first and fifth fingers are 

 pointed but less curved and clawlike than those of the middle fingers. 

 The usual paired sesamoids are present on the palmar sides of the 

 metacarpo-phalangeal joints. 



THIGH AND LEG. 



Plate XII, Figs. I, 3. 



The femur is slightly shorter and decidedly more slender than the 

 humerus. The shaft is cylindrical and nearly straight but the extremities 

 are considerably expanded. The head is supported on a slight neck and 

 is definitely directed forward as well as inward. Its smooth articular 

 surface is partially incomplete behind. The outer or greater trochanter 

 rises to the level of the top of the head and is inclined slightly inward so 

 that its apex is practically in the long axis of the shaft. Laterally it is 

 much compressed and it is only superficially separated from a broad 

 ridge extending distad a short distance to a small rounded protuberance 

 having a roughened surface and clearly representing a third trochanter. 

 This has approximately the same relations as the third trochanter in 

 Phascolomys, the only other marsupial except the extinct Wynyardia in 

 which there is any obvious development of the kind. The great tro- 

 chanter is bounded on the inner side by a deep slitlike digital fossa 

 which has as its other boundary a high thickened intertrochanteric ridge 

 almost as prominent as the great trochanter. This ridge runs from the 

 apex of the great trochanter distad with slight inclination toward the 

 lesser trochanter and then turning sharply and losing most of its eleva- 



