Dr. Wallicli on the Araoebai. 221 



My OWN Papees of 1863-4. — "The Hampstead form" 

 [Amoeba villosa, so named in the paper succeeding that from 

 which the present extract is taken) " corresponds in every 

 important particuhir with one found by me in Lower Bengal 

 in 1856j in which the villous portion of the ectosarc consti- 

 tutes a means of permanent attachment to foreign bodies, such 

 as Confervge or the like; and the animal appears to be nor- 

 mally sessile in its habits." — Ann. & Mag. Nat. Hist. April 

 1863, p. 290 *. 



" When evaporation of the water " (in my aquarium) " had 

 gone on to a greater extent, the entire granular mass referred 

 to became segregated, as if by a process of segmentation, into 

 numerous distinct nuclei^ amongst which a true nucleus was 

 not recognizable as a separate or different structure. These 

 multiple nuclei, varying in number from five to about a dozen, 

 were contained in no separate cavity or cavities, but occupied 

 the position previously occupied by the single large granular 

 mass. In the specimen exhibiting this structure the animal 

 seemed inclined to assume an encysted form, motion being 

 almost totally suspended." — Ann. (b Mag. Nat. Hist. May 

 1863, p. 368, pi. ix. fig. 5. 



" Another fact is deducible from the appearances presented 

 by the sarcode-substance of the largest of these Amoebce. 

 The rush of granules does not follow upon a previous con- 

 tractile effort exercised at the posterior portion. As the animal 

 progresses, occasionally altering its course, there are periods 

 during which perfect quiescence is maintained by the granules; 

 and the rush or flow of these seems to take place, as it were, 

 to fill up the vacuum engendered by the sudden projection of 

 a portion of the ectosarc in the shape of a pseudopodium. 

 Hence it w^ould appear that motion is dependent on the con- 

 tractile power of the external sarcode-layer, and that the 

 endosarc only passively participates in it. If this view is 

 correct, it involves a very important consideration ; for it 

 proves that the old German doctrine of a " primary contractile 

 mucus " is essentially correct, and that the circulation is not 

 dependent, even in part, on the alternate expansion and 

 collapse of the contractile vesicle. Further than this, it 

 affords the strongest confirmation of the high degree of dif- 

 ferentiation existing between the endosarc and ectosarc of the 

 Amoeban group. 



" The mysterious faculty resident in the latter portion of the 



* No description of tliis Bengal Amoeba had been published by me ; 

 but, as stated in a footnote to the above extract, in my ' North Atlantic 

 Sea-bed,' published in 1860, pi. iv. figs, 13 and 14, a, b, this remarkable 

 form is drawn in its occasional free and also in its sessile state. 



Ann. tfe Mag. N. Hist. Ser. 5. Vol. xvi. 16 



