.k ^ thee, , , 



idv 1 ^*'s 

 • . ^''' on 4e 



^^e to sav 



^, dev 



•■Almost 



) . on I 

 ^lopmenial 



ititti. 



er. 



of the observ 

 ^^'0"s, to which I k 

 ■^one^^ the Infcoi,, 



- " ^ ^ of encvstmeDt, « 



on'^ms: even to 



0"'0 



1 



oluiions of a given Hi 

 er of succession oto- 

 R-hich it contains. Ti 

 ,f the other ex 

 nly b}- no means 

 ,f'such succession. 



APPENDIX n. 



* 4 



CVil 



a 



Ki 



Euploies 



prominent green globules, probably a new species ; and 



lastly; colourless specimens of Ei 



charon, exhibited 



themselves, — all the species following each other in suc- 

 cession in the course of three weeks, a new form appearing 

 on the decline of a preceding, attaining its maximum in 

 number, and then decreasing in its turn to make room for 



+ 



the next in the series.' 



But can we even say that the developmental cycle is con- 

 fined to Amoeboid and Infusorial forms ? Very much un- 

 certainty undoubtedly exists on this subject, and the state- 

 ments of Agassiz, Gros, and others, however incredible they 

 may appear, should, we think, be kept in view as possibihties, 

 rather than summarily rejected on account of any a priori 

 considerations. 



have no tide to exist as a distinct class. ' Most of them,' he 

 says ^ ' far from being perfect animals, are only germs in an 

 ) a great extent. coEle- 1 early stage of development. The family of the Vorticellce 



.< 



Agassiz maintains that the Ciliated Infusoria 



exhibits so close a relation with Bryozoa, and especially with 

 the genus Pedicellina, that I have no doubt, that wherever 

 Bryozoa should be placed, Vorticella should follow and 

 be ranked in the same division with them. The last 



\ 



of Infi 



)f Cohn s 



jecompo^inS 

 s of Baker * 



2 ' 



jcera 



olor 



jdon ^^^" 



llus. 



r.; 



and 



^''ip 



1 o- " '*' 



» 



Bursaria, Paramecium, and the like 

 are^ as I have satisfied myself by direct investigation^ germs of 

 fresh-water wor7ns^ some of which I have seen hatched from 

 eggs oi Planar ia laid under my eyes 



But even if such observations are perfectly correct and true, 

 the evolution of a Ciliated Infusorium, out of the t^g of a 

 Planaria, would by no means necessarily carry with it the 

 counter proposition, that such Ciliated Infusoria were them- 



I 



^ * Ann. of Nat. Hist./ 1850, vol. vi. p. 156. 

 Mr. Girard confirms these statements, and maintains that Kolpoda 

 cucullus is one of the embryonic stages of fresh-water Planarice, 

 * Proceed, of American Associat.,' 1848, p. 402. 



