370 Dr. G. C. Wallich on an undescribed Indigenous AmoeJba. 



ticipates in it. If this view is correct, it involves a very import- 

 ant 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 

 differentiation existing between the endosarc and ectosarc of the 

 Amoeban group. 



The mysterious faculty resident in the latter portion of the 

 structure, of forming extempore orifices for the inception or ex- 

 trusion of food-particles, &c., may be witnessed in these speci- 

 mens in a very singular manner, and one which, as far as I am 

 aware, has not hitherto attracted attention. I allude to the 

 projection of the ectosarc from some area of the general surface 

 in the form of a hemispherical mass with a broad base, only a 

 very small portion of the original contour line seeming to give 

 way at first, so as to admit of the passage of the endosarc 

 and other granular contents into the newly projected part, but 

 its entire floor appearing to be gradually dissolved, as it were, 

 and free communication between the main body and the new 

 pseudopodial cavity not being established until the completion of 

 this process. Whilst it is progressing, the endosarc-granules seem 

 to rush round a corner into the cavity, the corner gradually re- 

 ceding, so to speak, and ultimately being altogether obliterated. 

 From these facts it is obvious that the ectosarc and endosarc 

 are not permanent portions of the Protean structure, but mutually 

 convertible one into the other ; and that it is an essential feature 

 of sarcode that, whilst the outer layer for the time being becomes, 

 ipso facto, instantaneously differentiated into ectosarc, the same 

 layer reverts to the condition of endosarc under the circumstances 

 Just described. In the latter part of the process, that is, the 

 reversion to the condition of endosarc, the action is by no means 

 so instantaneous as when the converse takes place. In the 

 Actinophryans both processes are, comparatively speaking, slow. 

 Lastly, I have to state that when the homogeneous sarcode is 

 poured forth from these Amoeba under pressure, the globules 

 show no tendency whatever to coalesce. In general, the 

 masses of sarcode are expelled in irregular- oblong or ovate 

 portions of varying sizes, which rapidly detach themselves, and 

 then at once assume a perfect spherical form. It is very rarely 

 indeed that foreign bodies remain within these masses, or are 

 extruded as part of their contents. They are extruded separately 

 under these circumstances. The sarcode constituting the sphe- 

 ules, when first it escapes, appears perfectly homogeneous, and 

 8 granules are extremely minute. After the lapse of a period 

 arying from a quarter tohalf an hour, this homogeneous cha- 



