llfi Mr. TI..T. Carter on the Orgnnisation of Infusoria. 



tluiU2;h it still retains great tenacity; nnd thus the expansions 

 of the siihjiieent tissue are seen to burst through it in niueh the 

 same manner that the end ol* a stream of lead bursts through 

 its ])elliclc. Finally, when all activity ceases, and the Annvha 

 becomes stationary (by fixing itself to some neighbouring object 

 through a jx-dicular prolongation of the ])cllicula), a new layer of 

 the latter is formed below the old one, and thus the cai)sule is 

 formed, and the pellicula replaced on the body of the Amwbn, 

 untd the latter becomes firmly encysted (I'l. V. figs. G, 8)*. 'I'o 

 w hat part of the body of the Amoeba the pedicular process cor- 

 resj)onds, I am ignorant; but it is interesting to see that in 

 Euylcim, where a similar ])rocess takes jdace, it is the anterior 

 extremity which is next the pedicle (tig. 9). Many freshwater 

 Kliizopoda si'crete a testaceous covering, which increases in size 

 with the animal ; but the lleshy part of the Ijody being for the 

 most part free, is of course still covered with pellicula. The 

 ])ellicula forms the surface-covering of Astasia and Eu/jlenaf, as 

 well as that of all the holo-,poly-, dip/o- and niono-ci\ia\.c(\ flexible 

 animalcules and zoospores. Here too, jirobably, the cilia them- 

 selves are also covered with it, though secreted by subjacent 

 organs, analogous perhaj)s to those which secrete the liairs on the 

 boilies of higher animals,— a suj)position that would a])])ear ridi- 

 culous did wc not find such a correspondence between the vital 

 j)rocesses of the highest and lowest developments as to induce us 

 to think the latter are but a repetition of the others on a snudler 

 scale; that is to say, effected by similar agents, of coiTes|)onding 

 minuteness, conducted on the same principle. Taking the 

 above view of the jiellicula, we must regard it as a structureless 

 j)rodu(t, which hardens after secretion. May we not infer that 

 tiiere is a layer below, specially organized for its formation ? 



Dif/phane. — By this name I would designate the moving 

 substance on which the pellicula rests (tigs. 1-3). Aviwha, 

 whose primary figure is spherical, has the power of changing 

 this into an almost unlimited number of secondary forms, most 

 of which, being attended with root-shaj)ed j)rolongatioiis, this 

 Infusorium is justly entith d to a place among the Khizopoda. 



* After this the numbers alone of the figures will be inserted, as they 

 are continuous throughout the three plates. 



f Although Astasia and Evijlena are licre mentioned together, it seems 

 that, in chis-ifieation, one shouhl he on the animal, and the other on the 

 vegetable side of Amn'ba; for Astasia possesses a mouth and eomplieuti d 

 buecal a])])aratus for biting off and taking in food, while Evylena ajjpears 

 to have no mouth, and to be nourislied In' cndosmosis. The half-deveJoped 

 cilium, too, in Euglcno, compared with the strong pix'hensile organ whieh 

 occurs in Astasia, with many other points wliicli will l)e mentioned here- 

 after, allies the former as much more to the zoospore or gonidium of the 

 Algae, as the reverse does the latter to the higher Infusoria. 



