THE AUSTRALIAN ORNITHORHYNCHUS. 



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root for worms in the mud, or catch insects and small animals. They 

 have a peculiar, fishy smell, and are eaten by the natives ; but this 

 is no sign that they are good, for the natives have no taste. They 

 belong to the lowest group of the mammalia, the Mbnotremata, 

 which includes the two genera Ornithorhynehus and Echidna , 

 both these genera exhibit an arrangement of the breast- and shoulder- 

 bones which is in a certain degree similar to that of the lizard and the 

 extinct ichthyosaurus. In all the higher mammalia, the humerus is 

 attached to the shoulder in a hollow of the scapula or shoulder-blade ; 

 in the ornithorhynehus, the hollow in which the ball of the humerus 

 rests contains a bone connected with the shoulder-blade called the cor- 

 acoid bone. The breast-bone in the mammalia consists of a broad 



Fig. 4. The shoulder- and breast-hones and ribs of the Echidna, a, T-shaped intermediate bone ; 

 b, manubrium ; c, the sword-shaped end of the breast-bone ; d, cartilaginous ribs ; e, key-bone; 

 /, the coracoid ; g, the epicoracoid bone. 



bone placed in front in quadrupeds, above the others in man, called 

 the manubrium, and several smaller bones, which reach down to the 

 belly, and have ribs on both sides ; while in the other mammalia the 

 manubrium is in contact with the neck-bone, in the ornithorhynehus the 

 two coracoid bones are in contact with the manubrium. Some other 

 bones are found on the breast and neck which are wanting in the other 

 mammalia : first, a T-shaped bone which joins the breast-bone from 

 below, and the cross of which bears at each end a neck-bone that 

 reaches to the shoulder-blade ; also, on each side in front of the cora- 

 coid bone, a so-called epicoracoid bone reaching to the neck. Some 



