178 DESCEiPTioN OF {Folygastnca. 



matic phenomena of motions which take place'without the intervention 

 or influence of the nervous system, when nothing was known of the 

 motion, very similar to a vohmtary one which exists even in plants j 

 this movement was certainly calculated to place the independent 

 animal nature of the spermatozoa beyond a doubt. But it is different 

 now. We know that motion is not an exclusive attribute of animals, 

 and that an inference respecting the animal nature of the formations 

 in question, however similar the motion observed in them may be 

 to that of animal organizations, is a very unsafe and venturesome one. 



We know that certain elementary constituents, animal as well as 

 vegetable, possess a power of movement, and that they retain it for 

 some time after having been separated from the organisms to which 

 they belonged. We only need here remind our readers of the so- 

 caUed ciliated epitheUum, the several ceUs of which swim about in 

 the fluid surrotmding them, and which, when in this state, have not 

 imfrequently, and that even qiiite recently, been considered as inde- 

 pendent animals ; how, further, the spores of the algae possess motion 

 by the aid of a ciliated investment, or of a single or manifold 

 long whip-like fibre, until they eventually become fixed and develope 

 themselves into a new plant. Such spores as these may be found 

 described and illustrated in the well known magnificent work of 

 Ehrenberg, classified as Infusoria, under the groups of Monadina, 

 Volvocina, &c. 



Under such circumstances we may consider ourselves perfectly 

 justified in declaring every attempt to prove the parasitic nature of 

 the spermatozoa by the characteristic of their peculiar motion, as 

 futile and inadmissable." 



Genus Spieodisctts. — The dish-spiral Animalcules are characterized 

 by developing themselves, through an imperfect self-division taking 

 place in an oblique direction, in elongated chains, or into inflexible 

 spirals, of a disc-like figure. Its organization is so little known that 

 Elu-enberg considers the genus as by no means satisfactorily deter- 

 mined. 



S. fulvus. — A lenticular spiral, of a yellowish brown colour. Arti- 

 culation indistinct. Group 62 represents three spirals, magnified 

 200 diameters. Found amongst conferva. Ereadth of spirall- 1200th. 



