102 TENTH ANNUAL REPORT OF 



ment is most directed to one sid3 or the other. Sometimes the little 

 spores, under the influence of these cilia, are seen to spin round and 

 round in widening circles ; but at other times change of direction, 

 pauses, accelerations, &c., take place during the voyage, which look 

 almost like voluntary alterations, or as if the spore were guided hy a 



princinlfi of thf njitnvfi of nniiTinl will Hptipp many ohsprvers do 



not he'sitate to call these moving spores animalcules, ^^n^ to consider 

 them of the same nature as the simpler infusorial animals. 



This, as it appears to me, is a conclusion which ought not to be 

 hastily assumed, not merely taking into consideration the extremely 

 minute size of the little bodies to^be examined, and the consequent 

 danger of our being deceived as to the cause of movement, and of its 

 interruption and resumption, but also remembering the facts ascer- 

 tained by Mr. Brown, of the movement of small particles of all mine- 

 ral substances which he examined. Many of the spores in question 

 are sufficiently small to come under the Brownian law, though others 

 are of larger size. Besides, if we regard the moving spores as animal- 

 cules we must either pdo\>t the ■'?p.r?.dox tli?.t ?. vegetable produces an 

 animal, which is then changed^ into a vegetable, and the process re- 

 peated through successive generations, every one of these vegetables 

 having been animal in its infancy; or else, notwithstanding their 

 strongly-marked vegetable characteristics, we must remove to the ani- 

 mal kingdom all Alga3 with moving spores. 



Neither of these violent measures is necessary, if we admit that 

 •mere motion, apart from other characters, is no proof of animality. 

 Though motion under the control of a will be indeed one of the char- 

 ter privileges of the higher animals, we see it gradually reduced as 

 we descend in the animal scale, until at last it is nearly lost alto- 

 gether. Long before we reach the lowest circles in the animal world, 

 we meet with animals which are fixed through the greater part of 

 their lives to the rocks on which they grow, and some of them have 

 scarcely any obvious movement on their point of attachment. In 

 some the surface, like that of the Algre spores, is clothed with cilia, 

 which drive floating particles of food within reach of the mouth ;_ in 

 others, even these rudimentary prehensile organs are dispensed with, 

 and the animal exists as a scarcely irritable flesh expanded on a frame- 

 work. This would seem to be the case in the corals of the genus 

 Fungia, if the accounts given of those animals be correct ; while in 

 the sponges the animal structure and organization are stilly farther 

 reduced, so as almost to contravene our preconceived notions of animal 

 will and movement. But the sponges can scarcely be far removed 

 from Fungia, nor can that be separated from other corals ; so that, 

 though I am aware some naturalists of eminence regard the sponges 

 as vegetables, I cannot subscribe to that opinion, but rather view them 

 as exhibiting to us animal organization in its lowest conceivable type, 

 and parallel to vegetable organization, as that exists in the lowest 

 members of the class of Alg;e. 



Tliis hasty glance at the animal kingdom teaches us that voluntary 

 motion is a character variable in degree, and at length reduced almost 

 to zero within the animal circle. On the other hand, we know that 

 movements of a very extraordinary character exist among the higher 



