1864.] OF BIRDS AND OTHER VERTEBRATA, 341 
In this bird I beheld a furcula with double branches, and saw 
that the V-shaped membrane-bone had, clamped upon each of its 
outspread arms, a wedge-like mass of feebly ossified cartilage. The 
whole matter flashed upon my mind in a moment, and I saw at once 
that the term “ clavicle’’ had been loosely and incorrectly applied to 
a part of the thoracic apparatus which is well developed in Frogs 
and Lizards, but continues rudimentary in Birds. 
Professor Huxley has assisted me greatly by putting into my hands 
a most valuable recent paper by Gegenbaur (‘“ Ueber die epister- 
nalen Skelettheile und ihr Vorkommen bei den Saugethieren und 
beim Menschen,” Abdruck a. d. Jen. Zeitschr. f. Medicin, ete. 
1864), in which this subject is beautifully worked out in many Mam- 
mals, and this additional cartilaginous piece, called by him “epi- 
sternum,” is shown to exist very frequently in this class also. 
Iam satisfied that these cartilagimous rods are really the homo- 
logues of the so-called clavicles of Lizards and Frogs ; whilst they 
have nothing whatever in common with the episternal pieces in the 
Chelonian, with the so-called episternal bone of the Lizards, nor with 
the episternal process in, Birds. Moreover the episternal piece or 
pieces in the Batrachia have nothing in common with the so-called 
*episternals”” of Gegenbaur. 
I shall close this paper by remarking that I wholly disclaim Pro- 
fessor Owen’s nomenclature of the scapular arch in osseous Fishes ; 
for there are only the two and the four well-known cartilaginous 
pieces in the whole structure, the supposed forearm and wrist ; 
whilst the so-called suprascapula, scapula, coracoid, clavicle, epicla- 
vicle, and the almost infinite joints of the symmetrical fin-rays, all 
these want names that will suit their nature*. 
It is just possible that the humeri of Cuvier (coracoids of Owen) 
may be the clavicles, and that they reappear as a single piece in 
Lizards and most Birds, and then in certain birds get back their 
separateness, which they retain throughout the Mammalian class. 
This view of them was taken by Spix, Geoffroy, Meckel, and Agassiz 
(see Owen’s Lectures on Comp. Anat. vol. ii. p.118). Still there is 
never such an inordinate growth of aponeurotic bone in this region 
in the air-breathing vertebrata. 
* T do not mention this part of the Fish as if no other region of its body had 
suffered from being dragged into harmony with that mischievous piece of fancy- 
work, ‘‘the vertebrate archetype.” It is high time for us to have ceased from 
transcendentalism : of what value is it? Our proper work is not that of straining 
our too feeble faculties at system-building, but humble and patient attention to 
what Nature herself teaches, comparing actual things with actual. 
