70 



ESSAY ON CLASSIFICATION. 



Part I. 



the type of their class. Few multiply in a direct, progressive development. As to 

 Echinoderms, they have for a long time almost entirely escaped the attention of 

 Embryologists, but lately J. Mliller has jjublished a sei'ies of most important investi- 

 gations upon this class/ disclosing a wonderful diversity in the mode of their develop- 



and Remarkable Animals of Scotland, etc., London, 

 1847, 2 vols. 4to, fig. — Forbes, (Ed.,) Monograph 

 of the British Naked-eyed Medusce, London, 1847, 

 1 vol. fol. fig. (Ray Society.) — On the Morphology 

 of the Reproductive System of Sertularlan Zoophytes, 

 etc., Ann. and Mag. Nat. Hist., 1844, vol. 14, p. 385. 

 — Agassiz, (L.,) Twelve Lectures, etc., q. a. — 

 Desor, (Ed.,) Lettre sur la generation, mtjdusipare 

 des Polypes Hydraires, Ann. Sc. Nat., 3e ser., 1849, 

 vol. 12, p. 204. — Krohn, (A.,) Bemerkungen iiber 

 die Geschlechtsverhiiltnisse der Sertularinen, Mid- 

 ler's Arch., 1843, p. 174. — Ueber die Brut des 

 Cladonema radiatum und deren Entwickelung zum 

 Stauridium, MuUer's Arch., 1853, p. 420. — Ueber 

 Podocorjnie carnea Sars und die Fortpflanzungsweise 

 ihrer medusenartigen Sprcisslinge, AViegm. Arch., 

 1851, L, p. 263. — Ueber einige niedere Thiere, 

 Muller's Arch., 1853, p. 137. — Ueber die friihesten 

 Entwickelungsstufen der Pelagia noetiluea, Miiller's 

 Arch., 1855, p. 491. — Kolliker, (A.,) Die Schwimm- 

 polypen, etc., q. a. — Buscn, (W.,) Beobachtungen 

 iiber Anatomic und Entwickelungsgeschichte einiger 

 wirbelloser Seethiere, Berlin, 1851, 4to. fig. pp. 1, 

 25 and 30. — Gegenb.\uer, KiJLLncER und MUl- 

 LER, Bericht iiber einige im Herbste 1852 in Messina 

 angestellte anatomische Untersuchungen, Zeitseh. f. 

 wiss. Zool., vol. 4, p. 299. — Gegenbauer, (C.,) 

 Ueber die Entwickelung von Doliolum, der Sehei- 

 benquallen und von Sagitta, Zeitseh. f. wiss. Zool., 

 1853, p. 13. — Beitriige zur n;ihern Kenntniss der 

 Schwimmpolypen (Sii)honophoren,) Zeitseh. f. wiss. 

 Zool., 1853, vol. 5, p. 285. — Ueber Diphyes turgida, 

 etc., Zeitseh. f. wiss. Zool., 1853, vol.5, p. 442. — 

 Ueber den Entwickelungscyclus von Doliolum, etc., 

 Zeitseh. f. wiss. Zool., 1855, vol. 7, p. 283.— 

 Feantzius, (Al. v.,) Ueber die Jungen der Cephea, 

 Zeitseh. f. wiss. Zool., voL 4, p. 118. — MUller, (.J.,) 

 Ueber eine eigenthiimliche Meduse des Mittelmeeres 

 und ihren Jugendzustand, Midler's Arch., 1851, p. 272. 



— ScHULTZE, (M..) Ueber die miinnlichen Geschle- 

 chtstheile der Camjoanularia geniculata, Miiller's 

 Arch., 1850, p. 53. — Hincks, (Th.,) Notes on the 

 Reproduction of the Campanulariadaj, etc., Ann. and 

 Mag. Nat. Hist., 2d ser., 1852, vol. 10, p. 81. — Fur- 

 ther Notes on British Zoophytes, Ann. and Mag. Nat. 

 Hist., 1853, vol. 15, p. 127. — Allman, (G. J.,) On 

 Hydroids, Rep. Brit. Ass. Adv. Sc., 1852, p. 50.— 

 Derbes, (A.,) Note sur les organes reproducteurs et 

 I'embryogenie du Cyanea chrysaora, Ann. Sc. Nat., 

 3e ser., 1850, vol. 13, p. 377. — Vogt, (C.,) Ueber 

 die Siphonophoren, Zeitseh. f. wiss. Zool., 1852, 

 vol. 3, p. 522. — Hsr.^EY, (Th. H.,) On the Anat- 

 omy and Afiinities of the Family of the Medusae, 

 Philos. Trans. Roy. Soc., 1849, IL, p. 413. — An 

 Account of Researches into the Anatomy of the 

 Hydrostatic Acalephis, Proc. Brit. Ass. Adv. Sc., 

 1851, p. 78. — Leuckardt, (R.,) Zoologische LTnter- 

 suchungen, Giessen, 1853-54, 4to. fig. 1st Fasc. — 

 Zur niihern Kenntniss der Siphonophoren von Nizza, 

 Wiegm. Arch., 1854, p. 249. — Stimpson, (W.,) 

 Synopsis of the Marine Invertebrata of Grand Manan, 

 Smithson. Contrib., 1853, 4to. fig. — Leidt, (Jos.,) 

 Contributions towards a Knowledge of the Marine 

 Invertebrate Fauna, etc., Journ. Acad. Nat. Sc, 

 Philad., 2d ser. 1855, vol. 3, 4to. fig. — See also 

 below. Sect. 20. 



^ Beskrivelser, etc., p. 37. — Ueber die Ent- 

 wickelung der Seesterne, Wiegm. Arch., 1844, I., 

 p. 169, fig. — Fauna littoralis, etc., p. 47. — MUller, 

 (.J.,) Ueber die Larven u. die Metamorphose der 

 Ophiuren u. Seeigel, Akad. d. Wiss., Berlin, 1848. — 

 Ueber die Larven u. die Metamorphose der Echino- 

 dermen, 2te Abh., Ak. d. Wiss., Berlin, 1849.— 

 Ueber die Larven u. die Metamorphose der IIolo- 

 thurien u. Asterien, Ak. d. Wiss., Berlin, 1850. — 

 Ueber die Larven u. die Metamorphose der Echino- 

 dermen, 4te Abh., Ak. d. Wiss., Berlin, 1852. — 

 Ueber die Ophiurenlarven des Adi'iatischen Meeres, 



