126 THE NATURAL HISTORY OF 



pial bones found in the kangaroo and other animals of 

 New Holland, &c. They are found floating in the mus- 

 cular walls of the abdomen ; and the only connection 

 they have with each other is by a very loose ligament. 

 From their position, they, as far as we can perceive, can 

 be of very little service to the animal, inasmuch as they 

 neither possess size nor strength sufficient to protect 

 the generative organs, or to guard, during the pregnant 

 state, the foetus within. However, there is not the 

 least doubt but these bones must answer some import- 

 ant purpose in the animal economy, else the allwise 

 Architect of the universe would never, in his wisdom, 

 have constructed an organ insubservient to some useful 

 function. 



THE ANATOMY OF THE THORACIC EXTREMITIES, 

 OR PECTORAL FINS. 



The whale being deprived of clavicles, or collar bones, 

 the pectoral fins are composed of the shoulder-blades, 

 and what are, strictly speaking, the pectoral fins. 



The Scapula or Shoulder-blade. — This is placed on 

 part of the last cervical vertebra, and partly on the first 

 dorsal, which it partly covers ; it is a very large bone, of 

 which the superior part is semicircular, and the inferior 

 nearly quadrangular. The external surface is extremely 

 smooth : there is no spinous process ; but one, analogous 

 to the acromion process of other animals, projects about 

 15 inches beyond the neck of the scapula. This must 

 afford attachment to some of the muscles ; the remain- 

 ing muscles must form connections with the smooth 

 surface, or with the superior margin of the bone. 



The costal or internal surface has several strongly 

 marked prominences and canals, which diverge towards 

 the semicircular margin. These canals are evidently 



