OF THE PROTOZOA. — ACTINOPHRYIIfA. 257 



jugation is not associated with the reproductive faculty. In fact, he has 

 never met with the development of an embrj'o in conjugated individuals of 

 his (Acinetiform) Actinophrys and Podophrya. Claparede questions {op. 

 cit. p. 286) whether the compound forms noted by Stein and Perty were, as 

 they supposed, all derived from conjugation ; and he proceeds to say that, if 

 it be proved that more than two individuals may thus be fused together, the 

 connexion of conjugation with reproduction will become exceedingly doubtful, 

 and that the term had better be di'opped, and either Stein's phrase " process 

 of fusion," or Ehrenberg's word " zygosis," adopted in its room. Whatever 

 value attaches to Claparede's deduction from the circumstance of more than 

 two being fused together, there can be no doubt that this may, and indeed does 

 frequently, happen. Lieberkiihn, one of the most recent investigators of this 

 group of beings (Zeitschr. 1856, 308), recognizes the occurrence, and observes 

 that the number united may be estimated by that of the contractile vesicles. 

 The process, he further asserts, is not one of genuine conjugation, but merely 

 a temporaiy cohesion ; for, after watching a group for six hours, he saw the 

 separation of the several component individuals, preceded by a narrowing of 

 the connecting bands or commissures. Such is an outline of the opinions and 

 statements of some leading naturalists respecting the nature and design of 

 this so-called act of conjugation. The balance of authority and evidence is 

 against the supposition of its reproductive purpose ; but when this view is 

 rejected, we have no other to replace it, and are sensible of the want of 

 sufficient data from dii'ect observation before a hopeful attempt can be made. 

 Ehrenberg, it should not be omitted to state {Monatsb. Berl. Akad. April 

 1854), started the notion that conjugation is intended as a means of invigo- 

 rating the species : " a curious idea," says Claparede {op. cit. p. 286), " and 

 not Y&vy reconcileable with the ordinary laws of nature." 



Kolliier {op. cit. p. 100) canvassed the question, if Actinophrjdna, along 

 with Rhizopoda, are to be considered cells, and, after an elaborate examina- 

 tion of the point, concluded that they must be regarded as peculiarly modified 

 simple cells. Claparede, after weighing Kolliker's arguments and reviewing 

 the stnictiu'al peculiarities of these animalcules, comes to the opposite conclu- 

 sion, viz. that, '' as regards ActinopTirys Sol in particular, we must either 

 drop the class of unicellular animals altogether, or refer this animal to some 

 other place." We do not deem it at all necessary here to enter upon this con- 

 troversy ; it has already engaged our attention in other places, and has of late 

 lost much of its interest by the extended modifications introduced latterly in 

 that particular hypothesis of ceU-natui^e, which, at the date of Kolliker's 

 paper in 1849, exerted so powerful an influence over the histological specu- 

 lations of all the writers of that period. 



Localities. — Actinophryina are inhabitants both of fresh and salt water. 

 They occur often as parasites upon the larger Protozoa, such as Stylonychia, 

 and on various small animals of other classes, and seem to draw nourishment 

 from them. They are also common among the filaments of Conferva and the 

 stalks of Lemna, where other animalcules congregate. Another locality is 

 amid the vegetable debris and minute animals which often float together, as 

 a dust-like film, on the surface of ponds. 



Affinities of Actinopheyina. — All recent writers refer this group of beings 

 to the Ehizopoda, except Siebold, who curiously enough retains Actinophrys 

 in the family Enchelia, along with Leucophrys and Prorodon, two genera of 

 Cihata of quite a difi'erent type of organization. Although the preceding 

 sketch of the history of Actinophryitui will afford ample evidence of many 

 homologies with the Rhizopoda, yet it will equally display not a few differ- 

 ential characters, sufficient, we believe, to separate them at least as a subclass. 



