44 
DE. W. KOWALEVSKI ON THE 
pisiform) on the outer end of the upper row. We find in the upper row, beginning 
from the inner side, the scaphoid, lunar, pyramidal, and pisiform ; in the lower, trape- 
zium, trapezoid, magnum, unciform. In all extinct Paridigitata, even those with a 
very reduced skeleton, we find the full number of these carpal bones (so in Anoplothe- 
rium , XijjJiodon, Hyopotamus, Plate XXXVII. figs. 2, 3, 20) ; and, only in consequence 
of the still greater reduction of the limbs, in some recent Ungulata one of the carpal 
bones (the trapezium) seems to be entirely lost, while another (the trapezoid) becomes 
confluent with the magnum ; that the trapezoid is not lost but is confluent with the 
os magnum, is shown by the two different points of ossification in the cartilage of the 
os magnum in young sheep. As we shall hereafter see, the number and shape of the 
carpal and tarsal bones of all animals belonging to the Paridigitate series present an 
extreme uniformity, individually as well as in their relation to one another and to 
the metacarpal and metatarsal bones; and this similarity is indeed so great that we 
cannot explain it in any other way than by community of descent. The extreme con 
stancy in the relations of these bones in all Paridigitata being ascertained, the problem 
which is unavoidably presented to the mind of the observer may be stated thus : — Very 
irregular small bones, intended to constitute a movable articulation between the long 
bones of the extremity and the metatarsals and metacarpals, arranged themselves in a 
certain way in reference to one another and to these metacarpals and metatarsals ; 
this arrangement remains the same in all Paridigitata, recent as well as fossil, 
notwithstanding the greatest diversity of form, size, and habits of life; and if some 
slight change is to be seen, it is due clearly to the overdevelopment of certain digits 
and consequent reduction of others ; but in all cases the reason of change is at once 
apparent : how can such similarity in animals so entirely different be explained \ To 
all naturalists who accept the gradual descent and differentiation of all Paridigitata 
from one common form, the fact must appear as a perfectly reasonable and intelligible 
one. If the immediate progenitor of the Paridigitates presented the given arrangement 
of the carpal and tarsal bones, then, at the gradual differentiation of this type, every 
small change in one bone called forth a corresponding change in all its neighbours. And 
as the link which connects all the forms together was never destroyed, and the changes 
were slowly going on, we meet now, in the extremely differentiated descendants, a unity 
of organization which was inevitable if all these forms descended from one common 
progenitor. But if, leaving the point of view of evolutionists, we look at the matter on 
the special-creation principle, this similarity of structure in animals so widely different 
is really an awkward fact. To the supporters of special creation the question presents 
itself in its simplest form thus : — We have now on the earth a large assemblage of 
Paridigitate mammals, presenting widely diversified generic and specific forms, fitted for 
the most different conditions of life, some leading an amphibious existence, sharing the 
large streams with Crocodiles, while others inhabit inaccessible rocks or burning sand 
plains, some heavy and sluggish, others light and swift, &c. ; and yet the creative force, 
in calling separately into existence these diversified forms, made them all on one plan, 
