356 MOLLUSCOUS WORMS. 



subject, and sponges were again held 1o be altogether insentient sub- 

 stances. Marsigli first, in modern times, declared them to be en- 

 titled to the rank of vegetables ; and Dr. Peysonell, towards the 

 middle of the last century, sent two papers upon this subject to the 

 Royal Society, both which are printed in its Transactions, in which 

 he maintained that they were not vegetables, but animals ; and point- 

 ed out what he conceived to be the mode of their growth and pro- 

 pagation. The idea had, indeed, been occasionally indulged for 

 nearly half a century antecedently ; but it was conceived too roman- 

 tic and visionary for general adoption : and hence all the natural 

 histories published at this period concur in the theory of Marsigli, 

 and Bauhine, Lobel, Tournefort, Hill, and alt the celebrated bota- 

 nists of the day, give them free admission into the vegetable king- 

 dom, and describe them as submarine plants. Ellis, however, seems 

 to have settled the point in 1 76*2 : his observations and experiments 

 were chiefly made upon the spongia tomentosa ; he satisfactorily 

 ascertained the existence of the animal inhabitant; remarked its 

 contraction within its cells when exposed to pain or injury; the ex- 

 piration and inspiration of water through its tubes ; and established 

 the position that sponge is an animal ; and that the ends or openings 

 of the branched tubes are the mouths by which it receives its nou- 

 rishment and discharges its excrement : a position which chemistry 

 has since abundantly supported by proving the ammoniacal property 

 of the cellular matter of sponge. 



There are forty-nine species of this zoophyte, of which the chief, 

 denominated from their shape or places of residence, are common 

 sponge; downy sponge ; grape sponge; lake and river sponge ; cox- 

 comb sponge. 



[Pantologia. 



SECTION IV. 



Molluscous Worms, or those without Shells. 



One of the simplest specimens we can refer to belonging to this 

 class, is the slug or Umax. Among the more curious we may men- 

 tion the following. 



1. Sepia, Cuttle, or Ink-fish. 

 This is one of the most extraordinary of the entire order. The 



