OSSEOUS SYSTEM. 15 



ate to be viewed as farther rudiments of phalanges. The number of 

 phalanges in a finger is seldom diminished to two (which is the usual 

 number in the thumb), or increased to 6 or 11 in the longest finger, 

 as in the Cetacea, where the Whale has 5 to 6, and there are even, 

 more in the Dolphin. In the Solidungula, and also in the Ruminan- 

 tia, the posterior phalanx of the finger is called the fetlock, the middle 

 the coronary, and the anterior which supports the nail or hoof, the 

 coffin bone. 



Between the metacarpus and the first row of phalanges are sit- 

 uated very generally certain sesamoid bones, called in the Horse 

 splint-bones. Others also lie between the first and second row of 

 phalanges, but are often wanting. Sesamoid bones lie between the 

 nail bones and middle phalanges, and are called in the Horse, Ru- 

 minantia, and Pachydermata, shuttle-bones. Where only one toe is 

 present, as in the Horse, the shuttle is single, but the splint-bone 

 double. The Edentata, e. g. Dasypus, Myrmecophaga, exhibit most 

 extraordinary proportions in the relative size of their different fingers. 

 In the Sloths the metacarpal bones are united together posteriorly, 

 and also with the front row of phalangeal bones. The fingers of the 

 Apes even of the higher species are distinguished from those of 

 Man by their length and slenderness, and the greater shortness of 

 the thumb, so that a perfect hand is found only in the human sub- 

 ject, theirs being more adapted for clasping trees in the act of 

 climbing. As a rule in the Cheiroptera, the thumb only is free, and 

 supports a claw, though this is the case sometimes with the index 

 finger ; the remaining slender, wire-like metacarpal and phalangeal 

 bones lie within the alary membrane. 



The Pelvis of the Mammalia is never so broad as in the human 

 subject, and its lateral walls are always smaller, flatter, and longer. 

 The iliac bones are broadest and most depressed in the Tardigrada, 

 the higher Apes, and the Elephant. In the rest of the Apes, the 

 Makis, and Carnivora, the iliac bones are much smaller and longer, 

 and the pelvis, owing to the backward recession of the pubic articu- 

 lation, are very oblique and narrow. The pelvis is much elongated 

 in the Cheiroptera, and especially in many of the Insectivora, where 

 it is either connected only at the pubic articulation by a small liga- 

 ment, or, as in the Mole and Shrew, is open in the form of a gap. 

 In many Cheiroptera it is completely open like that of the Bird. 

 The pubic articulation is frequently very deep ; it is formed also 

 by the ischia, and is very often converted into bone. In the Ar- 

 madilloes, as Dasypus, the ischia with the pubis are very broad, 



