onnections of the parts, just as homologies are determined in the last
of all the stages of development, the adult state. And since the
generalised type is shown most clearly in the earliest stages and tends
to become obscured by later differentiation, homologies observed in
embryonic life are to be upheld even if the relations in adult life seem
to indicate different interpretations.

[183] See review by Cuvier, _Mem. Mus. Hist, nat._, iii.,
pp. 82-97, 1817.

[184] _Mem. Savans etrangers_, vi. Extract in _Ann. Sci.
nat._ (2) i. (_Zool._), pp. 366-72, 1834.

[185] _Recherches sur la generation des Mammiferes_, 1834.
_Embryogenie comparee_, 1837.

[186] "Kiemen bey Saeugthieren," _Isis_, pp. 747-9, 1825.

[187] "Kiemen bey Voegeln," _Isis_, pp. 1100-1, 1825.

[188] "Ueber die Kiemenbogen und Kiemengefaesse beym
bebrueteten Huehnchen," _Isis_, xx., pp. 401-3, 1827.
(Read in Sept. 1826 to the _Versammlung der deutschen
Naturforscher und Aerzte_, then recently founded by
Oken).

[189] _Isis_, pp. 160-4, Pl. II., 1828.

[190] "Ueber die Kiemen und Kiemengefaesse in den Embryonen
der Wirbelthiere," Meckel's _Archiv_ for 1827, pp.
556-68. Also in _Ann. Sci. nat._, xv., pp. 266-80,
280-4, 1828.

[191] Meckel's _Archiv_, vi., pp. 1-47, 1832.

[192] _Untersuchungen ueber die Bildung und Entwickelung
der Fluss-Krebses_, Leipzig, folio, 1829. Preliminary
notice in _Isis_, pp. 1093-1100, 1825.

[193] "Untersuchungen ueber die Bildung und Entwickelung
der Wasser-Assel.," _Abh. z. Bild. u. Entwick.-Gesch._,
i., pp. 1-20, 1832. Translated in _Ann. Sci. nat._ (2),
ii., (_Zool._), pp. 139-57, 1834.

[194] Koelliker, _Entwickelungsgeschichte_, 2nd ed., p. 17,
Leipzig, 1879.

[195] _Handbuch der Entwickelungsgeschichte des Menschen
und ... der Saeugethiere und Voegel_, Berlin, 1835.

[196] _Embryogenie comparee_, 1837; _Histoire generale du
developpement des corps organises_, 1847-49.

[197] _Entwickelungsgeschichte des Kaninchen-Eies_,
Braunschweig, 1842; _Entwickelungsgeschichte des
Hunde-Eies_, Braunschweig, 1845;
_Entwickelungsgeschichte des Meerschweinchens_, Giessen,
1852; _Entwickelungsgeschichte des Rehes_, Giessen,
1854.

[198] "It is the role of embryology, as my great teacher
says, to form the court of appeal for comparative
anatomy, and it is