and other Indigenous Rhisopods. 435 



In addition to these crystalloids, which seem to occur more 

 largely in some individuals than in others, two other kinds of 

 corpuscles are to be found. Both have a spherical outline, and 

 are not discoidal, as may be seen on watching them roll over when 

 at the immediate extremity of a pseudopodium. They vary from 

 ^^i__th to YeVo^^ o^ ^^ ^°^^ ^° diameter, are devoid of any ap- 

 preciable cell-wall, even when examined under the higher powers 

 of the microscope, and are formed of a peripheral layer of pale, 

 nearly colourless, granular protoplasm surrounding a clear fluid 

 centre, the average diameter of which is about yu^oijth of an inch 

 (fig. 5). To these bodies (which are in aU probability identical' 

 mth the " discoid ovules " described by Carter, in his admirable 

 observations on the Organization of the Infusoria of Bom- 

 bay*, as occurring in A. Gleichenii, and as also seen in A. 

 verrucosa-f) I have applied the term nucleated corpuscles, as not 

 involving a function which must still be regarded as only hypo- 

 thetical, although I fully agree with Mr. Carter in the view that 

 these bodies perform some important part in the process of 

 reproduction. The second kind of spherical corpuscle to which 

 allusion has been made, although not nucleated as in the former 

 case, appears destined to exercise the function of a true ovule in 

 some of the Rhizopods, if not in all, as shall presently be shown ; 

 and therefore, taking into consideration the very marked re- 

 semblance of the latter, in all save the trivial item of depth of 

 colour, to the " yellow bodies '' met with in the Foraminifera, 

 Polycystina, Thalassicollidse, Acanthometrina, and two new fami- 

 lies I propose to establish for the reception of certain allied but 

 heretofore imperfectly understood pelagic genera, it appears 

 absolutely necessary to distinguish between the two kinds of 

 structure. 



To these bodies I have accordingly given the name of Sarco- 

 hlasts. In Amoeba they are somewhat larger than the nucleated 

 corpuscles, being from ^^^^th to y^th of an inch in diameter. 

 In their earlier stages they present a faint yellow tint, are some- 

 what oily-looking, but afterwards become almost colourless. 

 They are distinctly granular, nearly homogeneous throughout, 

 and, like the corpuscles, devoid of cell- wall (fig. 6). Both, how- 

 ever, are distributed equably through the endosarc, and take an 

 equal share in the pseudocyclosis which involves all foreign 

 matters and, under certain circumstances, the nucleus, con- 

 tractile vesicle, and vacuoles. 



There seems reason to believe that all organic substances in- 

 tended for food are invariably subjected to the digestive process 

 through the medium of vacuolar cavities specially extemporized 



• Ann. Nat. Hist. scr. 2. vol. sviii. pi. 5. fig. 5. f Ibid. vol. xx. p. 37. 



