420 HISTORY OF ZOOPHYTOLOGY. 



ill this department of natural history. In several essays pre- 

 sented subsequently to the Royal Society, and published in 

 their Transactions, he continued to illustrate and extend his 

 opinions, and defended them so successfully against his oppo- 

 nents, that they soon came to be very generally adopted. 



There was nothing unformed nor mystical in Ellis's opinion. 

 Certain marine productions, which, under the names of Litho- 

 phyta and Keratophyta, had been arranged among vegetables, 

 and were still very generally believed to be so, he maintained 

 and proved, with a most satisfactory fulness of evidence, to be 

 entirely of an animal nature — the tenements and products of 

 animals similar in many respects to the naked fresh-water 

 polype. By examining them, in a living state, through an 

 ordinary microscope, he saw these polypes in the denticles or 

 cells of the zoophyte ; he witnessed the display of their tenta- 

 cula for the capture of their prey, their varied actions and 

 sensibility to external impressions, and their mode of propaga- 

 tion ; he saw further that the little creatures were organically 

 connected with the cells and could not remove from them, and 

 that although each cell was appropriated to a single indivi- 

 dual, yet was this united " by a tender thready line to the 

 fleshy part that occupies the middle of the whole coralline," 

 and in this manner connected with all the individuals of that 

 coralline. The conclusion was irresistible — the presumed 

 plant was the skin or covering of a sort of miniature hydra ; 

 a conclusion which Ellis strengthened by an examination of 

 the covering separately, which, he said, was as much an ani- 

 mal structure as the nails or horns of beasts, or the shell of 

 the tortoise, for it differs from " sea-j^lants in texture, as well 

 as hardness, and likewise in their chemical productions. For 

 sea-plants, properly so called, such as the Algae, Fuci, &c., 

 afford in distillation little or no traces of a volatile salt ; 

 whereas all the corallines afford a considerable quantity, and 

 in burning yield a smell somewhat resembling that of burnt 

 horn and other animal substances, which of itself is a proof 

 that this class of bodies, though it has the vegetable form, yet 

 is not entirely of a vegetable nature."* 



* Dr. Good is in error when he states that the aramoniacal smell from burnt zoo- 

 phytes was the principal fact for placing them in the animal kingdom. Book of Na- 

 ture, i. 175 and 210. 



