124 THE BONES. 



inferior row (Fio;. 82, a). It is easy, therefore, to refer Man to the most perfect 

 pentadactylous type. 



2. Carnii'ora. — The hand of the Dog and Cat has five distinct digits, the 

 internal of which — the thumb — smaller than the others, does not reach the 

 ground (Fig. 82, b). By the metacarpus and the phalangeal section, these 

 animals belong, then, to the pentadactylous type. They appear to be removed 

 from it by the constitution of the carpus, for it has only seven (Dog) or eight 

 bones (Cat) ; there has been fusion of the lunar and scaphoid, but the fifth bone 

 of the upper row is free. The number of bones being thus raised to eight, we 

 know how they may be referred to the archetype — by proceeding in the same 

 manner as for the human carpus. 



3. Rodents. — The Rabbit has five digits, like the Cat, and nine carpal bones. 

 Five of the latter are in the upper row, in consequence of the duplication of the 

 fourth bone, which comports itself as in Carnivora. The scaphoid is between 

 the two rows, as in the tarsus. 



The Rabbit, therefore, only differs from the archetype by the fusion of the 

 first to the second inferior carpal bone, which sometimes is incomplete. 



We have thus demonstrated the pentadactylous composition of the hand in 

 the domestic Carnivora and Rodents — an easy task, as these animals have five 

 apparent digits. We will now pass to the Pig. 



4. Pig. — This animal has eight carpal bones and four complete digits, with 

 metacarpals and phalanges — two large and two small (Fig. 82, c). There is no 

 difficulty in referring the carpus of the Pig to that of Man or the Carnivora, and 

 from these to the archetype. It suffices to find in this creature a trace of the fifth 

 digit, in order to place it in the pentadactylous type. Normally, the fifth bone of 

 the lower row — the trapezium — has no relation with the bones of the metacarpus ; 

 which proves that the remainder of the thumb is absent. But this thumb has 

 been found entirely developed, and having the appearance of the other digits. 

 In Fig. M (c'), this has been shown in the teratological cases observed by 

 Joly and Lavocat, and Goubaux and ourselves. Consequently, although the Pig 

 has been classed among bisculcate animals by certain zoologists, yet it has in the 

 anterior limb five digits, more or less completely developed. 



5. Ruminants. — Intended as an organ of support, the hand of Ruminants 

 offers several fusions or abortions, which increase its solidity at the expense of 

 its suppleness and flexibility. Thus, in the first place, it appears more difficult 

 than in other animals to find, materially or virtually, the elements of the five 

 digits. 



Only six bones are found in the carpus of the 0-r, Sheep, and Goat ; but the 

 study of relations demonstrates that there are : abortion of the fifth bone of the 

 upper row ; fusion between . the first and second, and between the third and 

 fourth, and abortion of the fifth bone, of the lower row. So that, in reality, there 

 are met with, in the carpus of the domestic Ruminants, the elements of ten 

 bones, with the exception of two not developed (Fig. 82, d). 



The metacarpus comprises a principal metacarpal — the inferior articular face 

 of which is double — and a stylif orm bone placed alongside its external and internal 

 borders. For a long time, GeofFroy Saiut-Hilaire had demonstrated that the 

 principal metacarpal is formed by two metacarpals brought together during foetal 

 life, and separated by a more or less incomplete medullary septum during extra- 

 uterine existence. Besides, the isolation of the two metacarpals — temporary in the 

 Ox — is permanent in some other Ruminants, such as the Chevrotain of Guinea and 



