METAMORPHOSES OF ANIMALS. 103 



bracing the most recent investigations, having as yet been 

 published ; and I must take it for granted, that, before 

 forming a definite opinion upon the comparisons instituted 

 hereafter between the growth of animals and the structural 

 gradation among full-grown animals, or the order of suc- 

 cession of the fossils characteristic of different geological 

 periods, the necessary information respecting these changes 

 will have been gathered and mastered by my readers suffi- 

 ciently to enable them to deal with it freely. 



The embryology of Polypi has been very little studied 

 thus far ; and what we know of the embryonic growth of 

 these animals relates chiefly to the family of Actinoids. 1 

 When the young is hatched, it has the form of a little 

 club-shaped or pear-shaped body, which soon assumes the 

 appearance of the adult, from which it differs only by 

 having; few tentacles. The mode of ramification and the 



o 



multiplication by buds have, however, been carefully and 

 minutely studied in all the families of this class. 2 Acalephs 

 present phenomena so peculiar, that they are discussed 

 hereafter in a special section. Their young 3 are either 



and Mag. Nat. Hist., 2nd ser., 1852, (L.), Twelve Lectures, etc. p. 40 et 



vol. 9, p. 507. FORBES (ED.), On the seq. HAIME (J.), Me"moire sur le 



supposed Analogy between the Life Lerianthe, Ann. Sc. Nat. 4e ser., 1854, 



of an Individual and the Duration of vol.i. Note sur le developpement cles 



a Species ; Ann. and Mag. Nat. Hist., Actinies, Compt.-Rend., 1854, vol. 39, 



2nd ser., 1 852, vol. 10, p. 59. BRAUN p. 437 et 595. 



(AL.), Das Individuuni der Pflanze, 2 SeeDANA'sZoophytes,andMiLNE- 



q. a . Betrachtungen iiber die Er- EDWARDS et HAIME, Recherches, etc., 



scheinung der Verjungung in der Na- q. a., p. 44, n. 1. 



tur; Freiburg, 1849, 4to., fig. 3 SIEBOLD (C. Tn. E. v.), Beitriige 



1 SARS (M.), Beskrivelser og Jagt- zur Naturgeschichte der wirbellosen 



tagelser over nogle maerkelige eller Thiere, Neueste Schriften der Natur- 



nye i Havet ved den Bergeuske Kyst forsch. Gesellschaft in Danzig ; Dan- 



levende Dyr, etc.; Bergen, 1835, 4to. zig, 1839, 4to., p. 1-35. LOVEN (S. 



Fauna littoralis Norvegise ; Chris- L.),Beitrag zur Kentniss der Gattun- 



tiania, 1846, fol., fig. RATHKE (H.), gen Campanularia und Syncoryne, 



in Burdach's Physiologic, vol. ii, 2nd Wiegm., Arch., 1837, pp.249 and 321 ; 



edit., p. 215. Zur Morphologic, Rei- French Ann. Sc. n. 2de ser., vol. xv, 



sebemerkungen aus Taurien ; Riga p. 157. SARS (M.), Beskrivelser, q. 



und Leipzig,! 837, 4to., fig. AASSIZ a. Fauna littoralis, q. a. Einige 



