476 PROF. ST. GEORGE MIVART ON THE 
This view may be represented (with respect to the arm and hand) as in the annexed 
diagram :— 
Fig. 5. 
1, humerus; 2, intermedium (lunare); 3, centrale; 4, magnum; 5, 6, 7, & 8, metacarpal, and then pha- 
langes of middle digit; 9, radius; 10, radiale (scaphoid); 11, trapezium; 12, 13, 14, metacarpal and pha- 
langes of pollex; 15, trapezoides; 16, 17, 18, 19, metacarpal and phalanges of index digit ; 20, median half 
of unciforme; 21, 22, 23, and 24, metacarpal and phalanges of fourth digit ; 25, ulna; 26, ulnare (cunei- 
forme); 27, external half of unciforme ; 28, 29, 30, and 31, metacarpal and phalanges of the fifth digit. 
As Professor Huxley truly says!:—“The confirmation or refutation of this hypo- 
thesis is to be sought in development, and in the condition of the limbs in the 
Paleozoic Amphibia.” And he tells us that his suggestion is made “ mainly in the 
hope of stimulating investigation in both these directions.” 
Professor Huxley’s view is, I consider, the best yet suggested; but I cannot feel 
much confidence in its accuracy for all that. I cannot do so on account of the poly- 
morphic nature of the Elasmobranch fins, the multitudinous differences of which seem 
to point to protean transformations, and therefore to an extreme plasticity, which may 
have generated the cheiropterygium from any one of numerous possible sources. More- 
over Professor Huxley’s view seems to demand the unity of the centrale, while this 
carpal ossicle, deemed double by Gegenbaur in Jchthyosaurus and Plesiosaurus, has now 
been shown to be actually double, not cnly in Cryptobranchus, but in both limbs of three 
species of Siberian Urodeles?, while the representations given in the memoir referred 
to certainly do exhibit the tarsal and carpal structures rather as portions of oblique 
rays, proceeding radiad and distad from the ulnar side of the limb, than as disposed 
in harmony with Professor Huxley’s hypothesis. 
' P. Z. 8. 1876, page 57. 
* Namely, in Ranodon sibiricus, Salamandrella keyserlingii, and Salamandrella wosnefsenskyi. See Morpho- 
log. Jahrbuch, vol. ii. 3rd Heft, page 421, and plate xxix.: “ Die altesten Formen des Carpus und Tarsus 
der heutigen Amphibien,” by Dr. R. Wiedersheim. 
