22 HISTORY OF ZOOPHYTOLOGY. 



or new branches, which fall off on maturity, and adhere to any 

 stone, shell, or other hard body, by which they are protected 

 until the young are excluded. Now the outer coat of this egg 

 or seed is of a vegetable nature, and it throws out from the sides 

 in the manner of other seeds, certain little roots by means of 

 which it remains permanently attached ; but the internal part 

 of the egg or seed is anhnal, and growing simultaneously with 

 its vegetable covering, it is dispersed through all the ramifica- 

 tions and occupies their hollow interior, being developed into 

 polypes in the lateral denticles and extreme cells. Such was 

 the deduction he came to from observations made on the growth 

 more especially of the Sertularia abietina, which he had kept 

 alive for nearlv four months in a vessel of sea water. When 

 a new part was formed, there first emerged from the stem a mi- 

 nute tubular joint, which rose to four, five, or even eight lines 

 in height: after some days some lesser buds, regularly dispos- 

 ed in an alternate manner, were seen on the sides of this branch, 

 which in the course of four or six days grew into cells contain- 

 ing perfect polypes. Hence it is obvious to Baster that the 

 stem of this and similar zoophytes grows in thickness and length 

 as plants do, and that the medullary pith is animal, which it is 

 not wonderful should assume a dendroidal form, when we see 

 zinc and quicksilver do the same by the mere force of affinity. 

 Trembley had already pronounced the cells of the fresh-water 

 zoophytes (Plumatella) to be not the work of the polypes, but 

 rather compartments in which they concealed a part of their 

 body ; and this fact, added to those already given, makes it cer- 

 tain that the animalcules of the Sertulariadse are entirely pas- 

 sive, and have no more to do with their polypidoms than the 

 flower has with the increase and growth of the herb.* 



There is some ambiguity in Easterns statement of his opinions, 

 for it is not very obvious whether he believed the new formed 

 branchlets to be themselves the eggs or seeds, or whether they 

 only contained the eggs ; but be this as it may, it appears scarce- 

 ly doubtful that he knew nothing of the true ova and their cu- 

 rious ovaries. The phenomena observed in the production of 

 new parts are correctly stated, but nothing but wilful prejudice 



* Phil. Tniiis. Vol. Hi. p. lOe-118 For Baster's woiks see Hall. Bib. Bot. 



i. 4G8. 



