86 INTRODUCTION. 



blance to that letter. This he regards as analogous to the os furcatum, or 

 merrythought, in birds ; which, in the Adjutant, the Pelican, and one or 

 two more, is, indeed, ossified at its apex to the anterior point of the keel 

 of the sternum, and, in others, united by cartilage. Now, it is incon- 

 testable that the two transverse portions of this bone are real clavicles : 

 they are united to a process of the scapula, analogous to the acromion in 

 Man and other animals ; and their evident office is to keep the shoulders 

 firmly apart. 



The articulating cavity of the scapula, b, which receives the head of 

 the humerus, is deep, and from its lower margin a rhomboidal process, 

 c, c, is carried out, which, like the accessory, or coracoid clavicle of birds 

 (being, indeed, its analogue), rests upon the first true sternal bone, and 

 in part, also, against the lower limb of the letter-Y-bone. This process 

 is the coracoid projection of the scapula, enlarged, and continued to the 

 sternum, so as to form a second clavicle. It will be perceived, besides, 

 that there is a bone marked d, d, filling up, to a great extent, the space 

 between the coracoid clavicle and the handle of the Y-bone, which latter 

 it passes over. This portion occurs, but in a cartilaginous state, in the 

 Lizards ; and, indeed, it is partially cartilaginous in these lowest of the 

 Mammalia. 



On referring to the arm of the Echidna, in the preceding sketch, the 

 great strength and solidity of the humerus, with its bold projections, and the 

 large size of the radius and ulna, will appear very remarkable, justifying 

 an opinion expressed by Lieutenant Breton, that there is no quadruped 

 which possesses equal comparative powers.* The bones of the hand, or 

 paw, are solid, and compacted together, insomuch that the huge claws 

 seem to be the only indications of a digital division. The carpus is 

 broad and short, and composed of eight bones, irregular in their figure, 

 but fitted admirably together ; the metacarpal bones are as broad as 

 long ; the phalangal bones are short and thick, except the last on each 

 finger, which supports the nail. It is, at once, evident, that the organ, 

 thus fashioned, is expressly adapted for digging and excavating the solid 

 earth. The arm and hand of the Ornithorhynchus, though very powerful, 

 are more slightly made ; and the fingers, which are longer and more dis- 

 tinct, are connected together by webs, adapting the hand as an oar, in 

 conformity with the aquatic habits of the animal. Nevertheless, it is a 

 burrowing organ ; but the Ornithorhynchus makes its deep galleries in 

 the soft soil which composes the banks of rivers and stagnant waters. 

 It has been observed, that the Pangolins, and Great Ant-eater, have 

 no clavicles a circumstance which limits the action of the arms to 

 one kind of motion. These animals have immense power, and use 



* See Zoological Proceedings for 1834, p. 23. 



