^52. 



THE POLYPI. 



57 



This metamorphosis is completed when the skin is 

 covered by a lirown and solid layer, and neiv indi- 

 viduals are developed by gemmation from the two 

 Polyps (See Mei/cn, Isis, loc. cit.). I have seen 

 the development of the coralla of Cristatella mi- 

 rabilis and Plumatetla campanulata occur in 

 the same way. With the Cristateilae, gemmae of 

 new Polyps are often seen to arise from the skin, 

 even after the escape of the two Polyps, and before 

 the young colony has become at all fixed. At this 

 epoch of development these Polyps have been taken 

 by Cuvier for a distinct species, and called Crista- 

 tella mucedo. See Roesel, loc. cit. p. 559, Taf. 



XCI. ; and Turpin, Ann. d. So. Nat. TIT. 1837, p, 

 65, pi. II. and III. 



Infusoria-like embryos have been observed also 

 hySteenstrup(i:nte)LS\ich. loc. cit. p. 66, Taf. I. fig. 

 21) with Coryne sguamata, and by Sar.i (Faun. 

 Uttoral. Norveg. p. 7, Tab. II. fig. 7-11) with Po- 

 docoryna carnea. The round eggs moving about 

 by means of cilia, which Bcid (Ann. of Nat. Hist. 

 XVI. p. 392, 397, pi. XII. fig. 9, 13) has observed 

 in the visceral cavity of Pediceltina echinata, 

 and in special capsules with Flustra avicularis, 

 were probably embryos also.* 



* [§ 52, note 3.] The embryonic development &c., Mem. Acad. Bruxelles. XIX. See also AU- 

 of the Bryozoa has been carefully wrought out by man, lleport, loc. cit. 1850, p. 322 — Ed. 

 f^an Beneden. See Recherch. sur les Bryozoaires, 



