ZOOPHYTA ASCIDIOIDA, 245 



of cells are formed, and in several the multiplication goes on in 

 a regular arithmetical progression ; but in others the cells are 

 heaped together without apparent regularity, as in Alcyonella 

 and Alcyonidium, where the softness of all the parts seems to 

 allow of a non-regulated succession of buds. The general dis- 

 position of the cells, however, in this order is certainly after the 

 quincunx, affording examples which the learned Sir Thomas 

 Browne would have gladly adduced in proof that " Nature geo- 

 metrizeth and observeth order in all things, and of the generality 

 of this mystic figure." Nor indeed were they entirely overlooked 

 by this observant physician. " The spongy leaves of some sea- 

 wracks," he says, " Fucus, Oaks, in their several kinds, found 

 about the shear, with ejectments of the Sea, are over-wrought 

 with net-work elegantly containing this order (the quincunx) : 

 which plainly declareth the naturality of this texture ; and how 

 the Needle of Nature delighteth to work, even in low and 

 doubtful vegetations."* 



Whilst the composite individual is thus increased by gemmules 

 or buds, the species is propagated and diffused by means of ciliat- 

 ed ova, of which the source has been a matter of some difference 

 of opinion among naturalists. There appear at certain seasons, 

 on many of these zoophytes, round pearly testaceous bodies 

 which are placed on or above the mouths of the cells. Ellis 

 believed these to be their matrices or ovaries " which, in time," 

 he says, " may unfold and extend themselves into those many 

 beautiful tree-like forms that we find them in."f This opinion 

 was also adopted by Pallas, because of the seasonal appearance 

 of the bodies in question, and because they are found only over 

 full-^rown and matured cells.! No one after this seems to have 

 held other belief, § until recent discoveries, demonstrating the 

 complexity of the organization of this order, rendered the exis- 



• The Garden of Cyrus, p. 33. Lond. 1686. folio. 



f Essay on Corallines, p. xi Ellis's earlier conjectures, which, being erro- 



■neous, it is unnecessary to detail, may be seen in Phil. Trans, abridg- (an. 

 1753) X. p. 346. 



I Elench. Zoophytorum, p. 36. 



§ " I am inclined to consider them as ovaria enclosing the germs of future 

 individuals ; having observed that these vesicular bodies are sometimes whole, 

 and in this case I have always found them filled with small globular bodies." 

 Lamonroux, Corall. p. 58. 



