THE SKELETON IN THE FLYING LEMURS. 197 



external border, and rather lower, there is still another and smaller 

 process, which is the third trochanter. Between these two projections 

 on the posterior aspect of the bone, the shaft is veiy smooth and partie- 

 nlarly flat. N"o spiral line joins the greater and lesser trochanters on 

 the anterior surface of the bone, while posteriorly, the trochanteric line 

 is very feebly pronounced in the corresponding locality. Both these lines, 

 or intertrochanteric ridges, are very noticeable in the femora of many 

 other mammals, man included. 



At the distal end of the shaft the two condyles are strong and thick. 

 They are almost exactly of the same size and neither one is lower on the 

 shaft than the other, as is sometimes the case among mammals where the 

 inner condyle is the lower of the two. 



The smooth, convex, articular surfaces seen posteriorly on these 

 condyles are practically of exactly the same size, and they terminate in 

 the same transverse planes, both above and below. Between them is a 

 deep, sharply defined, intercondyloid notch, that terminates abruptly at 

 the lowest plane of the bone and superiorly in a similar manner on a flat 

 surface named in anthropotomy the popliteal space. Again, either the 

 internal or external condyle exhibits upon its outer surface a distinct pit, 

 or depression, wherein certain muscles arise or are inserted. One is about 

 as well marked as the other, as are the tuberosities that occur, one in 

 each ease, above them. The one on the outer condyle is the outer tubero- 

 sity, and the other the inner tuberosity. Anteriorly, the intercondyloid 

 space is of a nearly quadrilateral outline ; it is smooth, slightly narrower 

 above than below, gently concave from side to side, and roundly convex in 

 the longitudinal direction with respect to the axis of the shaft. This 

 surface is shown in figure 6. 



The patella is poorly developed in Cynocephalus. It may, or may not, 

 be completely performed in bone, and there is reason to believe that in 

 young specimens it will always be found in cartilage or at the best in 

 very elementary osseous tissue. When in bone it is not large, though 

 it extends from a point opposite the center of one condyle to a point 

 opposite the center of the other, being parallelogi'amatic in outline, with 

 the long sides transverse. Anteriorly, the patella is convex from above, 

 downward, and correspondingly concave posteriorly. The tendon in 

 which this sesamoid is embedded, the quadriceps extensor, is very tough 

 and strong and is inserted on the free anterior border of the head of the 

 tibia. 



The tibia is the longest bone in the skeleton of this animal ; it is, 

 however, by no means the stoutest, being exceeded in this respect by both 

 the humerus and the femur. Proximally the tibia has a shaft the caliber 

 of which about equals that of the femoral shaft at the junction of its 

 upper and middle thirds, but as we pass to the distal end this caliber 

 gradually diminishes until just before arriving at the lower end of the 



