136 Dr. G. C. Wallich on the Value of 



specimen he alludes to "was composed of an irregular crystalline 

 aggregate, based aj)parenthj upon an octahedral form," the two 

 measurements of the single crystalloid are probably nearly 

 identical. 



Contrary to the opinion expressed by Mr. Carter, I found that 

 the crystalloids of A. villosa are of the hexahedral series*, and 

 occur as such even in the smaller specimens. Whether the 

 crystalline state be the primary one or not, I am at present un- 

 able positively to say, although it seems highly .probable ; for 

 the association with them of rounded granules, of nearly similar 

 size, in some but by no means in all specimens, although per- 

 haps indicative of the latter being a rudimentary condition of 

 the former, cannot be accepted as a proof of the fact, any more 

 than that in the oldest specimens, which sometimes present both 

 the granules and the crystalloids, the former necessarily consti- 

 tute a disintegrated stage of the latter. In my Streatham spe- 

 cimens of A. villosa, when first procured, the roundish granules 

 were almost entirely absent. Now (July 3) they are nearly as 

 plentiful as the crystalloids. On this head I have only to ex- 

 press my obligation to Mr. Carter for calling to my recollection 

 that I had inadvertently omitted to allude to Auerbach's dis- 

 covery of crystalloids in A. bilimbosa, although fully alive to the 

 fact when I penned my paper — more particularly as Auerbach 

 regards the crystalloids as hexahedral, which is the view I adopt 

 with regard to those of A. villosa and the other forms in which 

 those bodies have been detected by me (Annals, June, pi. 10. 

 fig. 7). 



Mr. Carter says that he observed the villous appendage in 

 1854; but it would appear that he failed to recognize its nature 

 or office ; for, writing in the 'Annals ' in 1856 (vol. xviii. p. 116), 

 the following passage occurs : — " Finally, when all activity 

 ceases and the Amoeba becomes stationary (by fixing itself to 

 some neighbouring object through a pedicular prolongation of 

 the pellicula^), a new layer of the latter is formed below the old 

 one, and thus a capsule is formed, and the pellicula replaced on 

 the body of the Amoeha, until the latter becomes firmly encysted. 

 To what part of the body of the Amoeba the pedicular process 

 corresponds I am ignorant; but it is interesting to see that in 

 Euglena, where a similar process takes place, it is the anterior 

 extremity which is next the pedicle." This is precisely the re- 

 verse of the position of the prehensile portion in A. villosa, un- 

 less, indeed, Mr. Carter means to convey that the villous region 



* I have succeeded in mounting these crystalloids in balsam, by which 

 their true shape is very distinctly brought out under a |th or -j^th objective. 



t Proving that at this period be entertained a different view with regard 

 to its adhesive quaUty, 



