IIG 



• K NOV/ LEDGE 



[Feb. 23, 1883. 



fore-limbs in these animals. The coracoid process over- 

 liani,'s a sliallow, saucer-like space, called the glenoid cavity. 

 Into tills ciivity the upper arm-bone (or hicmentu) fits, and 

 thus forms the xhviih/d-juinl. 



Tlie clavicle or cullar-bom: is the second of the shoulder- 

 girdle bones. It is a narrow bone, shaped somewhat like 

 tiie letter S. It rests by its inner end on the top of the 

 breast-bone, and by its outer end is attached to the " acro- 

 mion process " of the scapula. No collar-bones exist in 

 hoofed animals (horse, cow, etc.), or in seals and whales. 

 They are small in carnivorous animals, whilst bats, apes, 

 and other animals possess them in perfect array. 



The fore-limb of man consists (1) of a single bone, that 

 of the upper arm, called the humerus ; (2) of two bones 

 forming the forearm, and called rat/jus and ulna; (3) of 

 eight small bones, forming the carpus or wrist ; (4) of five 



bones (one for each finger) forming the palm or metacarpus ; 

 and (.5) of the five digits or fingers. The fingers, with the 

 exception of the thumb, :ire composed of three small bones 

 called phalavges. The thumb has only two phalanges (as 

 one may see by looking at it), and there are, therefore, 

 fourteen phalanges in each hand. 



Holding the arm with the palm of the hand forwards or 

 upwards (when the limb is said to be in supination), the 

 radius is that bone in the fore-arm which lies to the thumb- 

 side, the ulna, its neighbour bone, lying to the little-finger 

 side of the limb. This is the natural position of these bones 

 in man, and the bones lie parallel, as just described, and as 

 seen in the right arm of the skeleton we havedepicted. Now, 

 turn the palm downwards or backwards. This action, of 

 extreme utility to man, is popularly supposed to be effected 



by a " turn of tlie wrist." This is not the case. In turn- 

 ing the palm backwards or downwards, the radius rung 

 round and crosses the ulna, so that in this changed posture 

 (known as prvnntiou), the relations of the bones are 

 altered. The bones should, therefore, always be described 

 naturally, with the palm forwards and with the radius and 

 ulna lying parallel. It is interesting to note that in many 

 animals (cat, dog, and carnivora generally ; elephant, ic), 

 the }iroHK position, with the radius crossing the ulna (as in 

 the left arm of the skeleton depicted above), is the fixed 

 and natural state of the fore arm. 



Five is the greatest number of fingers developed in 

 mammals. They may diminish in number to four (in 

 the dog), three (rhinoceros), two (in sheep, camel, ic), or 

 one (in the horse). The thumb may be wanting, as in 

 spider - monkeys ; and birds want the fourth and fifth 

 fingers. In whales, the number of the phalanges (or small 

 bones of the fingers) may be much increased from their 

 numbers in man's digits. In the third finger of a species 

 of whale, as many as fourteen phalanges are found. 



The loirer (or hind) limb is attached to a girdle 

 familiarly named the haunch. This haunch, or pelvis, 

 consists (l) of part of the spine (sacrum), already described, 

 behind, and (2) of two haunch-bones or innominate bones, 

 which are united in front. The sacrum is, in fact, firmly 

 wedged in between the two haunch-bones behind. 



Each innominate, or haunch-bone, consists in reality of 

 three bones. There is (1) the ilium, forming the expanded 

 part of the haunch ; (2) the ischium, upon which the body 

 rests in sitting; and (3) the pubis, or front portion, which 

 joins its neighbour of the opposite side. There is no trace 

 in the adult of the threefold composition of the haunch- 

 bones ; but it is only about the twenty-fifth year of life 

 that final union and firm ossification of the three bones take 

 place. On the outer side of each haunch-bone is a deep 

 cup. This is the acetabulum, in which the head of the 

 thighbone rests to form the hip-joint. 



The lower limb consists of (1) the./('»i(;r, or thigh-bone, 

 the longest bone in the body ; which, below, joins (2) the 

 leg, consisting of the tibia (or shin), wliicli receives the 

 lower end of the thigh-bone and the ^fibula, a long, slender 

 bone lying to the outside of the leg ; (3) the tarsus, or 

 ankle, consisting of seven bones (one less than in the 

 wrist ; (4) the metatarsus, or "instep " and (5) the digits, 

 or toes. The composition of the toes (of fourteen phalanges) 

 is exactly that seen in the fingers. 



There is a close correspondence to be noted between the. 

 skeleton of the fore and hind limbs. For we see that 

 whilst humerus and thigh correspond, fore-arm and leg^ 

 wrist and ankle, and toes and fingers also show a marked re- 

 semblance. How these resemblances have arisen, is a. 

 difficult question to determine. Perhaps the shortest and 

 safest fashion of solving it is to allege, what development 

 seems to teach — namely, that the fore and hind limbs have 

 been developed from a common type, and owe their diver- 

 gences to the dift'erent uses which, in the economy of 

 animal forms, they have come to subserve. 



We must lastly note that the knee-cap, or patella, is 

 not, properly speaking, a bone of the skeleton. It is not 

 developed, as the other bones are, but is formed in the 

 tendon or sinew of the great muscle of the front of the 

 thigh. Such bones are called sesamoid bones. We find 

 these bones developed in other situations, where the 

 tendons or sinews exert great pressure on the parts over 

 which they move. 



The mileage of the passenger trains of the North- 

 Eastern Railway Company during the last half of 18S2 

 was 4,871,8-18; gODds and mineral trains, 7,322,729. 



