78 



ESSAY ON CLASSIFICATION. 



Part I. 



approximate more the type of the Trematotls. The Sipunculoids appear to be more 

 closely related to the Annulata than to the Holothurioids.^ 



The class of Crustacea, on the contrary, may be considered as one of the best 

 known, as far as its zoological characters and embryonic growth are concerned ; the 

 only point still questioned being the relationship of the Rotifera.^ In their mode 

 of development the Lerna3ans, the Entomostraca proper, and the Cirripeds agree as 

 closely with one another as they differ from the higher Crustacea. Tliis con- 

 formity^ is the more interesting, as the low position the Entomostraca hold in the 



Worte zur Entwickelungsgeschiclite der Eunice, niit 

 einem Naehworte von Kiilliker, N. Denksch. Schw. 

 Gesell., 1847, vol. 8, 4to. fig. — Quatrefages, (A. 

 DE.) Memoire sur rEmbryogenie des Annelides, Ann. 

 Sc. Nat. 3e ser., 1848, vol. 10, p. 153, fig. — Desor, 

 (Ed.,) On the Embryology, etc., q. a. — Leidy, 

 (Jos.,) Descriptions of some American Annelida 

 abranchia, Journ. Ac. Nat. Sc. Phil. 1850, vol. 2, 

 p. 43, fig., (Lumbricillus contained several thousand 

 large Leucophrys. The case related here by Leidy 

 seems to me to indicate rather the hatching of Opali- 

 nas from the eggs of Lumbricillus, than the presence 

 of parasitic Leucophrys.) — Schultze, (M.,) Ueber 

 die Fortpflanzung durch Theilung bei Nais probosci- 

 dea, Wiegman's Archiv, 1849, L, p. 293; id. 1852, 

 L, p. 3. — Zoologische Skizzen (Arenicola piseat.) 

 Zeitsch. f. wiss. Zool. 1852, vol. 4, p. 192. — Busch, 

 (W.,) Beob. fiber Anat. und Entw. q. a. (p. 55.) — 

 Ml'LLEK, (M.,) Observationes aimtomica; de Vermi- 

 bus quibusdam maritimis, Berolini, 1852, 4to. ; Miil- 

 ler's Archiv, 1852, p. 323. — Ueber die weitere 

 Entwickelung von Mesatrocha sexoculata, Miiller's 

 Archiv, 1855, p. 1. — Ueber Sacconereis helgolandica. 

 Mailer's Archiv, 1855, p. 13. — Kroiin, (A.,) Ueber 

 die Ercheinungen bei der Fortpflanzung von Syllis, 

 "Wiegman's Archiv, 1852, L, p. CG. — Ueber die 

 Sprosslinge von Autolytus prolifer Gr., Miiller's Ar- 

 chiv, 1855, p. 489. — Leuckart, (R.,) Ueber die 

 ungeschlechtliche Vermehrung bei Nais proboscidea, 

 Wiegman's Archiv, 1851, p. 134. — Ueber die Ju- 

 gendzustande einiger Anneliden, Wiegman's Archiv, 

 1855, L, p. 63. 



■* Peters, (W.) Ueber die Fortpflanzungsorgane 

 des Sipunculus, Miiller's Archiv, 1850, p. 382. — 

 MiJLLER, (M.,) Ueber eine den Sipunculiden ver- 



wandfe Wurmlarve, Mailer's Archiv, 1850, p. 439. 



— Krohn, (A.,) Ueber die Larve des Sipunculus 

 nudus, etc., Miiller's Archiv, 1851, p. 368. — 

 SciisiARDA, (L.,) Zur Naturgeschichte der Adria 

 (Bonellia viridis) Denksch. Wien. Akad. 1852, vol. 

 4, p. 117, fig. — Gegenbauee, (C.,) Ueber die Ent- 

 wickelung von Doliolum, der Seheibenquallen und 

 von Sagitta, Zeitsch. f. wiss. Zool. vol. 5, p. 13. 



" Ehrenberg, (C. J.,) Die Infusionsthierchen, 

 etc., q. a. — Dalrymple, (.J..) Description of an In- 

 fusory Animalcule allied to the Genus Notommata. 

 Philos. Trans. 1844, II., p. 331. — Naegeli, (H.,) 

 Beitriige zur Entwickelungsgeschichte der Eiider- 

 thiere, inaug. Diss., Zurich, 1852, 8vo. fig. — Leydig, 

 (Fr.,) Ueber den Bau und die systematische Stel- 

 lung der Raderthiere, Zeitsch. f. wiss. Zool. 1854, 

 vol. 6, p. 1. — Zur Anatomic und Entwickelungsges- 

 chichte der Lacinularia socialis, Zeitsch. f. wiss. Zool. 

 1852, vol. 3, p. 452. — Cohn, (F.,) Ueber die Fort- 

 pflanzung der Raderthiere, Zeitsch. f. wiss. Zool., 

 1855, vol. 7, p. 431. — Huxley-, (Th. H.,) Lacinula- 

 ria socialis. Trans. M. Sec, Micr. Journ. 1852, p. 12. 



— Williamson, (W. C.,) On the Anatomy of Meli- 

 certa ringens. Quart, Micr. Journ. 1852, p. 1. 



' .Jurine, (L.,) Histoire des Monocles qui se 

 trouvent aux environs de Geneve, Paris, 1806, 4to. 

 fig. — Edw.\rds, (H. Milne,) in Cuvier, Regn. An. 

 edit, illustr. q. a. Crustaces ; represents young Li- 

 mulus. — Zaddach, (E. G.,) De Apodis canerifor- 

 mis Anatome et Historia evolutionis Bonnre, 1841, 

 4to. fig. — NoRDMANN, (Al. V.,) Microgr. Beitr. q. 

 a. — Leydig, (Fr.,) Ueber Argulus foliaceus, ein 

 Beitrag zur Anatomic, Histologic und Entwickelungs- 

 geschichte dieses Thieres, Zeitsch. f. wiss. Zool. 1850, 

 vol. 2, p. 323. — Ueber Artemia salina und Branchi- 



