772 The American Naturalist. [September, 
early embryo, and represent, morphologically, the radiale, 
intermedium, centrale and ulnare. In the distal series there 
are also two free elements, one of them (carpal II-III) being 
evidently compound. 
Diaorrs. There are four distinct metacarpals. The first (II) 
supports two phalanges, the second three, the third one, and 
the fourth none. The distal phalanges of m. c. II and III 
are furnished with claws. M. C. V arises as a distinct digit, 
subsequently becomes free, and finally unites with m. c. IV. 
NuwBERING OF Diaits. The persistent digits of the birds 
wing are either I, II and III or II, III and IV, the bulk of 
evidence being in favor of the latter enumeration. 
LITERATURE CITED. 
'66 Coues, Elliott. The osteology of Colymbus Me : 
with notes on its myology. Memoirs Bost. Soc. N. Hist., 
131, 1866. 
'87 Coues, Elliott. Key to North American Birds. Third 
Edition. Boston, 1877. 
'00 Heusinger, C. F. Zootomische Analekten. II. Ein Bei- 
trag zur Metamorphose des Vogel-Flügels. Meckel's Archiv f. 
d. Physiol., vi, 546, 1820. 
"2 Huxley, Thomas Henry. A manual of the anatomy 
of vertebrated animals. London, 1871. 
'93 Hurst, C. Herbert. Biological Theories, VIII. The 
digits in a bird's wing; a study of the origin and multiplica- 
tion of errors. Natural Science, iii, 275, 1893. 
'88 Jackson, W. Hatchett. Forms of Animal Life... by 
thelate George Rolleston. Second Edition. Oxford, 1888. 
'83 Johnson, Alice. On the development of the pelvic gir- 
dle and the skeleton of the hind limb in the chick. Quar. 
Journ. Micr. Sci., xxiii, 399, 1883. 
'81 Jeffries, J. A. On the fingers of Birds. Bulletin 
Nuttall. Ornith. Club, vi, p. 6, 1881. 
"2 Morse, Edward S. On the Tarsus and Carpus of 
Birds. Ann. Lyceum Nat. Hist., N. Y., x, 1872. 
'06 Owen, Richard. Aride * Aves" Todd’s Cyclopedia 
of Anatomy and Phys., i, p. 265, 1836. 
