xtn 



PHYLUM CHORDATA 



507 



suture is often recognisable between it and the scapula until a 

 comparatively late stage. In the young condition (when the foetus 

 is attached to the teat) the coracoid is comparatively extensive and 

 reaches the pre-sternum ventrally. A clavicle is always present, 

 except in the Bandicoots, but may be incomplete. There is never 



orti 



it. 



IV 



cbd 



Fia. 1143. Skeleton of "Wallaby (HaliHulnrus ualabatus). The scapula is represented as 

 raised somewhat higher than it would be in the natural relations of the parts. The head of 

 the femur has been separated from the acetabulum. acet. acetabulum ; acr. acromion 

 process ; ast. astragalus ; calc. calcaneum ; cbd. cuboid ; chev. chevron bones ; cl. clavicle ; 

 cun. cuneiform of carpus ; epi. epipubis ; fb. fibula ; fern, femur ; hd. head of femur ; hu. 

 humerus ; il. ilium ; isch. ischium ; obt. obturator foramen ; orb. orbit ; pis. pisiform ; pub. 

 pubis; rad. radius; rb.l, first rib ; rb.13, last rib; so. scapula; st. sternum; tb. tibia; troch. 

 great trochanter of femur ; uln. ulna ; unc. tinciform ; IV. fourth toe. 



a distinct centrale in the carpus. In the Opossums the ilium has 

 the primitive form of a straight, three-sided rod. In the Kan- 

 garoos (Fig. 1143, il.) it is still simple and three-sided, but somewhat 

 curved outwards ; in the rest it is more or less compressed. In 

 nearly all the Marsupials there is a pair of epipubic or marsupial 



