REPORT ON THE SEALS. 17 



tubercle were unossified, but the fusion of the three segments of the bone in the 

 acetabulum was complete. The interval between the two pubic bones at the symphysis 

 was of considerable width. 



Posterior Extremity. — The femur was 173 mm. long, and was characteristically 

 flattened, its greatest width at the condyloid end being 100 mm. The head was smooth 

 and without a depression for the ligamentum teres. The trochanter major was well 

 marked, but there was neither trochanter minor nor trochanter tertius. The anterior 

 flattened surface of the shaft was divided by an oblique ridge, which separated the 

 crureus and vastus externus, and extended from the neck downwards and outwards 

 towards the outer condyle, and on the back of the shaft there was a faint linea 

 aspera. The trochlear surface for the patella was shallow and not continuous with the 

 articular surfaces of the condyles, from which it was separated by an intermediate rough 

 area, to which was attached a broad, strong, ligamentous band connected with the lower 

 end of the patella and the deep surface of the ligamentum patella. This band would 

 separate the patello- femoral joint from the femoro-tibial joints and was doubtless morpho- 

 logically the same as, though histologically different from, the ligamentum adiposum of 

 the human knee-joint. The condylar articular surfaces were feebly convex and separated 

 from each other by a roughened intercondylar fossa.. The epiphyses in one of the larger 

 femora were separable from the shaft, but in the other fusion had commenced. 



The patella was 45 mm. in its long axis and 41 mm. transversely ; its trochlear 

 articular surface was feebly concave and not facetted. Its cutaneous surface was 

 roughened. At its upper end it was 26 mm. thick, and at its lower end only 12 mm. 



The tibia was 340 mm. long, and the. fibula was 336 mm. They articulated with each 

 other above and below, and the shafts were separated in the upper three-fourths by an 

 interosseous interval of some width, but in the lower fourth they were closely approximated 

 and united by an intermediate ligament. Each bone had a malleolar prolongation at 

 the lower end, but that of the tibia was very short, and did not articulate with the 

 inner surface of the astragalus. The tibia had a broad surface superiorly, smooth on 

 each side for the femoral condyles, but rough between for the attachment of the semi- 

 lunar cartilages and crucial ligaments. The shaft of the tibia was almost straight and 

 possessed a ventral surface and ridge for the insertion of the gracilis, semitendinosus, and 

 semimembranosus tendons. Above this ridge was the surface of attachment of the 

 ligamentum patellae, fibulad to which the shaft was grooved for the tibialis anticus. The 

 posterior surface of the tibial shaft was grooved for the origin of the tibialis posticus, the 

 tendon of which also grooved the back of the lower end of the bone. The fibula was a 

 much more bulky bone than in the human leg, so as to give broader surfaces for the 

 origin of muscles ; two peroneal grooves marked the lower end of the shaft and the 

 external malleolus. The epiphyses at both ends of each leg bone were not fused with 

 the shafts. 



(ZOOL. CHALL. EXP. PART LXVIII. — 1887.) ^JJ 3 



