Chap. I. 



METAMORPHOSES OF ANIMALS. 



V3 



be very vmitomi, but tlioy diflbr fri'oatly as to tlieir breeding, many laying their 

 eggs before the germ is formed, whilst others carry them in their gills until the 

 young are entirely formed.^ This is observed particularly among the Unios, some of 

 which, however, lay tlieir eggs very early, while others carry them for a longer 

 or shoi'ter tune, in a special pouch of the outer gill, which presents the most diversi- 

 fied forms in different genera of this family. Nothing is as ^-et known of the 

 develo^iment of Brachiopods. The Gasteropods^ exhibit a much greater diversity 



rembiTop^'iiie, ranatomic et la pln-siologic de? Asci- 

 dies simples, Jlom. Ac. Brux., 1847, vol. 20. — 

 Krohn, (A.,) Uebcr die Entwiekelung dcr Ascidion, 

 Muller's Arch., 1852, p. 312. — Kolliker, (A.,) 

 et LowiG, De la composition ct de la structure 

 des envcloijpes dcs Tunicicrs, Ann. Sc. Nat. 3e ser., 

 vol. 5, p. 193. — Huxley, (Tii. II.,) Observations 

 upon tlie Anatomy and Physiology of Salpa and 

 Pyrosoma, Philos. Trans. R. Soc, 1851, II., j). 5G7. 

 — EscnuicHT, (D. F.,) Anatoniisk-physiologiske 

 Undersogelser over Salperne, Kiob. 1840, fig. — 

 Steenstrui", (J.,) Uebcr den Generationsweehsel, 

 q. a. — VoGT, (C) Bildcr aus deni Thierlcljcn, 

 Frankfurt a. M., 1852, 8vo. — Muller, (II.,) Ucber 

 Salpen, Zeitsch. f., wiss., Zool., vol. 4, p. 329. — 

 LEUCiiART, (R.,) Zoologishe Untersuchungen, Gies- 

 sen, 1853-54, 4to., fig., 2d Fasc. 



* Carus, (C. G.,) Entwickelungsgeschichte unse- 

 rer Flussmuschel, Leipzig, 1832, 4to., fig. — Qtjatre- 

 Fages, (Arm. de.) Sur I'embryogenic des Tarets, 

 Ann. Sc. Nat., .3e scr., 1849, vol. 2, p. 202. — Sur 

 la vie iuterbranchiale des petites Anodontes, Ann. Sc. 

 Nat., 2de ser., vol. 5, p. 321. — Loven, (S. L.,) Om 

 Utvecklingen of Mollusca Aeepliala, Ovei-s. Vet. 

 Akad. Forhandl. Stockholm, 1849. — Germ. ]\Iiillcr's 

 Arch., 1848, p. 531, and Wiegnian's Arch., 1849, 

 p. 312. — Prevost, (J. L.,) De la generation chez la 

 moule des peintres, Mem. Soc. Phys. Geneve, 1825, 

 vol. 3, p. 121. — SciiMii>T, (0.,) Ueber die Entwieke- 

 lung von Cyclas calyculata Drap. Miiller's Arch., 

 1854, p. 428. — Leydig, (F.,) Ueber Cyclas cornea, 

 Mailer's Arch., 1855, p. 47. 



" Carls, (C. G.,) Von den iiussern Lebensbe- 

 dingungen der weiss- und kaltblUtigen Thicrc, Leip- 

 zig, 1824, 4to., fig. — Prevost, (J. L..) De la 

 g^n(5ration chez le Lymnee, Mem. Soc. Phys., 



10 



Geneve, vol. 5, p. 119. — Sars, (^I.,) Zur P^ntwieke- 

 lungsgeschiehte der Molkisken und Zoupliyten, 

 ■\Viegm. Arch., 1837, I., p. 402; 1840, I., p. 190.— 

 Zusiitze zu der von mir gegebenen Dartstellung 

 der Entwickelinig der Nudibraiidiien. Wiegm. Arch. 

 1845, I. p. 4. — C^uatrefages, (Arm. de,) Memoire 

 sur I'Embryogenie des Planorbes et des Lymnees, 

 Ann. Sc. Nat., 2de ser., vol. 2, p. 107. — VaxBexe- 

 DEX, (P. J.,) Recherches sur le developpement des 

 Aplysies, Ann. Sc. Nat., 2de ser., vol. 15, p. 123. — 

 VanBexedex, (P. J.,) et Wixdischmax, (Ch.,) 

 Recherches sur I'Embryogenie des Limaces, Mem. 

 Ac. Brux., 1841. — Jacquemix, (Em.,) Sur le 

 developpement des Planorljcs, Ann. Sc. Nat., vol. 5, 

 p. 117; Nov. Act. Nat. Cur., vol. 18. — Dumor- 

 TiER, (B. C.,) Memoire sur les evolutions de 

 I'embrj-on dans les Mollusques Gasteropodes, Mem. 

 Ac. Brux., 1836, vol. 10. — Laurext, (J. L. M.,) 

 Observations sur le developpement de I'oeuf des 

 Limaces, Ann. Sc. Nat., vol. 4, p. 248. — Pouchet, 

 (F. A.,) Sur le developpement de I'embrj-on des 

 Lymnees, Ann. Sc. Nat., 2de ser., vol. 10, p. 63. — 

 VoGT, (C.,) Recherches sur I'Embryologie de I'Ac- 

 fa;on, Ann. Sc. Nat., 3e ser., 1846, vol. 6, p. 5. — 

 Beitrag zur Entwickelungsgeseliichte eincs Cepha- 

 lophoren, Zeitseh. f. wiss. Zool., 1855, vol. 7, p. 162. 



— ScnuLTZE, (M..) Ueber die Entwiekelung des 

 Tergipes lacinulatus, Wiegm. Arch., 1849, I., p. 268. 



— Warxeck, (N. A.,) Ueber die Bildung und 

 Entwiekelung des Embryo bei Gasteropoden, Bull. 

 Soc Imp., Moscou, 1850, vol. 23, L, p. 90. — 

 SciiMiDT, (0.,) Ueber die Entwiekelung von Limax 

 agrestis, Miiller's Arch., 1851, p. 278. — Leydig, 

 (F.,) Ueber Paludina vivipara, ein Beitrag zur 

 niihem Kenntniss dieses Tliieres in embryologiseher, 

 anatomiseiier und histologischer Bcziehung, Zeitseh. 



