Chap. I. 



METAMORniOSES OF ANIMALS. 



(9 



chiss of Crustacea, agrees strikingly with their early ajipearance in geological times, 

 while the Ibrm of the adult Cirripeds^ and that of the Lernoeans Avould hardly 

 lead one to suspect their near relationship, Avhich has, indeed, heen quite overlooked 

 luitil Einl)r3-ology showed that their true position is among Crustacea. In the 

 development of the higher Crustacea/ their superior rank is plainly exhihited, and 

 few types show more directly a resemblance, in their early stages of development, 

 to the lower members of their class, than the Brachyura. 



In the class of Insects, I include Myriapods, Arachnoids, and the true Insects, 

 as, according to the views expressed hereafter, these natural groups constitute only 

 different degrees of complication of the same coniljination of organic systems, and 

 must, therefore, be considered as natural orders of one and the same class. This 

 class, though very extensively studied in a zoological and anatomical point of view, 

 and as far as the habits of its representatives are concerned, still requires, however, 

 much patient work, as the early embryonic development of these animals has been 

 much less studied than their later transformations.^ The type of the Arachnoids 



juis stnj^iialis, Zt'itsch. f. viss. Zool. 18.51, vol. 3, p. 

 280. — VanBeneden, (P.J.,) Recherches sur quel- 

 ques Criistaccs inferieurs Ann. Sc. Nat. 3e ser. 1851, 

 vol. 16, p. 71. — Muinoire sur le developpement et 

 I'organisation dcs Nicothoes, Ann. Se. Nat. 3e ser. 

 1850, vol. 13, p. 354. — Barrande, (J.,) Syst. sil. q. 

 a. ; contains the first observations upon the transfor- 

 mations of Trilobites. 



^ Thompson, (W. V.,) Zoological Researches 

 and Illustrations, or Natural History of nondescript 

 or imperfectly known Animals, Cork, 1828-34, 8vo., 

 fig. — Bl'RMElSTEU, (II.,) Beitrage zur Naturge- 

 schichte dcr Rankenfiisser, (Cirripedia,) Berlin, 1834, 

 1 vol. 4to. fig. — GooDSiR, (II. U. S.,) On the Sexes, 

 Organs of Reproduction, and Development of Cirri- 

 peds, Ed. N. Phil. J. 1843, No. 35, p. 88, fig.— 

 Martin St. Ange, (G. J.,) Memoire sur I'organisa- 

 tion des Cirripedes et sur leurs rapports naturels 

 avcc les animaux acticules, Ann. Sc. Nat. 1831, 

 p. 366, fig. — Darwix, (Cu.,) A Monograph of tlie 

 sub-class Cirripedia, wiili Figures of all llic Sjiecies, 

 London, 1851, 2 vols. 8vo. (Ray Society.) — Bati;, 

 (SrENCE.) On the Development of the Cirripedi.i, 

 Ann. and Mag. Nat. Hist. 2d ser. vol. 8, p. 324. 



' Rathke, (II.,) Untersuchungen iilxr die Bil- 

 dung und Kiilwickelung dcs Flusskrebses, Leipzig, 



1820, 1 vol. fol. fig. — Beitrage zur Fauna Norve- 

 gica. Act. Nov. Ac. Leop. Cass. vol. 20. — Beitriige 

 zur vergleichenden Anatomic und Physiologic, Rci- 

 scbemerkungen aus Skaiidinavien, Dantzig, 1842, 

 4to. — Zur Morphologie, Reisebemerkungen aus Tau- 

 rien, Riga und Leipzig, 1837, 4to. fig. — Uebcr die 

 Entwickelung der Decapoden, Miiller's Archiv, 1836, 

 p. 187, Wiegman's Archiv, 1810, L, p. 241.— 

 Beobachtungen und Betrachtungcn liber die Entwi- 

 ckehing der Mysis vulgaris, Wiegman's Archiv, 1839, 

 p. 195, fig. — Erdl, (M. p.,) Entwickelung des 

 Ilummei-eies, Miinchcn, 1843, 4to. fig. — Edwards, 

 (II. Milne,) sur la generation des Crustaces, Ann. 

 Sc. Nat. 1829. — Observations sur les changcments 

 de forme que divers Crustaces eprouvent dans le 

 jcune age, Ann. Sc. Nat. 2de ser. vol. 3, p. 321. 

 — Agassiz, (L.,) Zoological Notes, etc., Am. .Jour. 

 Sc. and A., 1852, p. 420. — Recent Researches, etc., 

 Am. .Tourn. Sc. and A., 1852, vol. 16, j). 136. 



" IIi:i!OLi>, (M..) Entwickelungsgeseliiilite dcr 

 Schinellrrliiige, etc., Kassel und Marburg, LSI,"), 4to. 

 fig. — Disquisitiones de animalium verlebris caren- 

 tium in ovo formatione, Frankfurt a. M., 1835, fol. 

 fig. — Rathke, (II..) Entwickelungsgeschiehte dcr 

 Blatta germanica, Meckel's Archiv, 1832. — Zur 

 Entwickelungsgeschiehte dcr Maiilwurfsgrillc (Gryl- 



