PROTOZOA ACTINOPHRYS. 



407 



FIG. 192. 



any great difficulty to an observer, who can devote sufficient 

 attention to the study. 1 



262. Nearly allied to the preceding, is another curious organism, 

 on which the attention of many eminent Microscopists has been 

 recently fixed. This creature, the Actinophrys (Fig. 192), con- 

 sists like the preceding of a homogeneous, jelly-like contractile 

 substance, or sarcode, not enclosed in any distinct envelope, 

 though the outer portion seems to be of firmer consistence than 

 the inner. Throughout the body, which is usually nearly spheri- 

 cal in form, but more particularly near its surface, there are ob- 

 served vacuoles occupied by fluid ; these have no definite 

 boundaries, and may be easily made artificially either to coalesce 

 into larger ones, or to subdivide into smaller. A " contractile 

 vesicle" (0), pulsating rhythmically with great regularity, is 

 always to be distinguish- 

 ed either in the midst of 

 the jelly-like substance, 

 or (more commonly), 

 near its surface; and the 

 appearance which it pre- 

 sents in this latter posi- 

 tion, seems to leave no 

 doubt of its being in- 

 cluded within a distinct 

 though very thin mem- 

 brane. The " sarcode" 

 extends itself into con- 

 tractile tentacular fila- 

 ments, which are called 

 pseudopodia; and these, 

 in the Actinophrys sol, 

 are commonly seen to 

 radiate from the centre, 

 in such a manner as to 

 have suggested the de- 

 signation of the species. 

 Their degree of extension, however, is extremely variable, and 

 sometimes they entirely disappear: the creature cannot then be dis- 

 tinguished with certainty from an Amoeba. For although the form 



1 It has been recently affirmed by Dr. Hartig, that Jtmuebce may be produced by the 

 transformation of the " antherozoids" of Chara ( 202), Marchantia, or Mosses ; and 

 that, in their turn, they become metamorphosed, first into Protococci or other unicellular 

 Algae, and then into Articulated Algae. But even if jelly like bodies resembling 

 AmoebaB in general appearance and in spontaneous change of form, should be thus pro- 

 duced, they cannot be said to be true Amoebae, unless they should feed in the manner 

 described above, which Dr. Hartig does not appear to have witnessed. (See " Quart. 

 Journal of Microscopic Science," vol. iii, p. 51.) However strange Dr. Hartig's state- 

 ments may be, they are not more strange than many assertions of the same class first 

 appeared, which are now admitted as unquestionable truths ; and they ought not to be 

 set aside without disproof, any more than they should be received without further con- 

 firmation. 



Actinophrys sol, in different states : A, in its ordinary sun- 

 like form, with a prominent contractile vesicle, o; B, in the 

 act of division or of conjugation, with two contractile 

 vesicles, o, o; c, in the act of feeding; D, in the act of dis- 

 charging faecal (?) matters, a and 6. 



