ARKIV FÖR ZOOLOGI. BAND 7. N:0 10. 



a little 

 so that 

 31/2 cm. 

 there is 

 The 

 capsuls 

 bones. 

 capsule. 

 of the 



below the latter. It is rather strongly corapressed 

 the greatest thickness at the distal end is only about 



Along the middle of the shaft on the outer side 

 a raised but blunt keel. 



pelvis as well as the femur are enclosed in a thick 

 of fibrous tissue which can be easily peeled off the 

 If this is done the cartilages remain fixed at the 



The largest cartilage is the one covering the end 

 pubis. It extends for about 7 cm. along tliis bone 



Fig. 3. The connection between the pubic bone 

 and the feniur of Balcena australis. 



and attains a thickness of nearly a centimeter. Another carti- 

 lage of the same thickness and nearly the same size — it 

 measures about 5 em. in a straight line — is curved round 

 the proximal end of the femur (fig. 1). These two cartilages 

 are united by fibrous tissue except at a circular area with a 

 diameter of about 2 cm. (conf. fig. 3 and 5). This area is flat 

 and smooth as well on the pubic as on the femoral side 

 and between them is a flat cavity of the shape of a piece 

 of money (conf. fig. 4). This cavity is undoubtedly the 

 remains' of the acetabular (synovial) cavity between capiit 

 femoris and pelvis. As the figure (fig. 3) shows this ace- 

 tabular cavity is not situated at the end of the triangulär 

 pubic rudiment but on the side of the same which joins the 



