516 DE. J. MUKIE ON THE ANATOMY OF THE SEA-LION. 



iliac synchondrosis. Measurements: — Extreme pelvic length 7 - 3 inches, ilium 3*1, 

 pubis 4-2, as is also ischium to mid-acetabulum ; the latter 1*3 long, anterior iliac 

 angles 3-3 apart, mid iliac breadth or depth 1*2, line cutting acetabulum 1*7, mid 

 ischio-pubal 1*3. Diameters of brim — conjugate 4*7, transverse 1*5, oblique 3'3. 

 Diameters of outlet — antero-posterior T4, transverse 0*4. 



Femur and Patella. The former, at its upper end, has head and trochanteric 

 eminence on a level simulating one another — and neither prominent, from the antero- 

 posterior flattening and breadth of the short shaft. The intercondyloid fossa is shallow, 

 the innermost knuckle largest, and both rather square in figure from being truncate 

 below. Femur is 4 inches long. Patella small, rounded, and with a flat articular 

 surface. 



Tibia and Fibula. The straight rodlike fibula usually stands quite behind the tibia ; 

 its narrowed shaft is sharply triangular. Head badly defined, smaller end more 

 expanded. The tibia has a forward bend, a somewhat laterally compressed stoutish 

 shaft, and subequally enlarged extremities. The articular end opposed to the femur is 

 smooth and pretty equal-surfaced ; but it shelves downwards, backwards, and outwards. 

 This posterior inclination is most serviceable, and, indeed, enables the femur to be bent 

 on the lower limb at a very acute angle without depriving the muscles of their power 

 of action in walking. Moreover, along with unusual freedom of the femur, it 

 contributes to the limb being thrown back and up in a line with the tail as in the act 

 of swimming. There is a short inner malleolus ; and the adjoining astragaloid face has 

 double facets. Extreme length of tibia 8*2, of fibula 6*5 inches. 



Hind Foot. When the animal is on all fours the tarsal bones, of the normal number, 

 offer perhaps less striking and fewer, but as singular points worthy of notico as the 

 carpus. The entire sole (and not a segment of it) is laid on the ground plantigrade- 

 fashion in walking. Both astragalus and calcaneum are low. Cuvier's words (I. c. 

 p. 226), so applicable to Otaria jubata, will bear quotation. lie says : — " L'astragale 

 des phoques est tres-extraordinaire, en ce qu'au lieu d'une poulie plus ou moins creuse 

 dans son milieu il offre a la jambe une poulie convexe formee de deux faces, qui font 

 ensemble un angle saillant comme un toit, et dont Tune repond au tibia, et l'autre, qui 

 est plus grande, au perone. Cet os n'a pas seulement une apophyse en avant pour le 

 scaphoide, mais il en a une autre en arriere terminee par une tuberosite et formant une 

 sorte de talon interne, de maniere qu'en voyant l'astragale isole on croiroit que c'est le 

 calcaneum." I may note more particularly of the present specimen that the horizon- 

 tally ovoid fibular facet looks backwards and inwards, and there is a certain amount of 

 the same obliquity apparent in its tibial concavo-convex facet. These dispositions 

 concurrently adapt themselves to the peculiarities of tibia and fibula. The plantar 

 surface of the os calcis is roughened and moderately convex ; the short calcaneal process 

 seems to have an inward tilt. It is not altogether, as Cuvier observes, that the 

 calcaneum is placed outside the astragalus, but rather that the two bones have a 



