HISTORY OF ZOOPIIYTOLOGY. 15 



putation as a philosophical inquirer, and is even to this day the 

 principal source of our knowledge in this department of natural 

 history. In several essays presented subsequently to the Royal 

 Society, and published in their Transactions, he continued to 

 illustrate and extend his opinions, and defended them so suc- 

 cessfully against his opponents, 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 mi- 

 croscope, he saw these polypes in the denticles or cells of the 

 zoophyte ; he witnessed them display their tentacula for the cap- 

 ture of their prey, — their varied actions and sensibility to ex- 

 ternal impressions,^ — and their mode of propagation ; 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 individual, yet was this 

 united " by a tender thready line to the fleshy part that occu- 

 pies the middle of the whole coralline,"" and in this manner con- 

 nected with all the individuals of that coralline. The conclu- 

 sion was irresistible — the presumed plant was the skin or cover- 

 ing 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 animal structure as the nails or 

 horns of beasts, or the shell of the tortoise, for it differs from 

 " sea-plants 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 ammoniacal smell from burnt 



