446 Dr. G. C. Wallich on Amoeba villosa 



phrys and Difflugia (also from Hampstead) which, although not 

 specifically new, offer some important and, if I mistake not, 

 hitherto unnoticed characters. 



As is well known, in A. Sol the body consists of a spherica 

 or nearly spherical mass of sarcode, the external layer of which 

 is said to be permanently distinct from the endosarc, notwith- 

 standing the admission that no definite boundary-line is traceable 

 between these two portions of the structure, and that they in- 

 sensibly merge one into the other. Carpenter* describes it as 

 follows : — "The pseudopodia seem to be derived from the ectosarc 

 alone, the endosarc not extending itself into them. They pos- 

 sess, moreover, a degree of consistence which usually prevents 

 them from coalescing when they come into contact with one 

 another ; and whenever such a coalescence does take place, it 

 is to a much smaller extent than is common among Foraminifera." 

 And again, " Although the existence of a nucleus in Actinophrys 

 has been denied, its presence (in certain species at least) must 

 be regarded as a well-established fact." Speaking of the incep- 

 tion of food, he says, " The body taken in as food is received 

 into one of the vacuoles of the endosarc, where it lies, in the 

 first instance, surrounded by liquid." . . . . " Several vacuoles 

 may be occupied at one time by alimentary morsels ; frequently 

 from four to eight are seen thus filled, and occasionally ten or 

 twelve, Ehrenberg having in one instance counted as many as 

 sixteen." 



From what has been already advanced by me with regard to 

 Amoeba, it almost follows that I should view with extreme doubt 

 the specific value of the characters assigned by different writers 

 to the various forms of Actinophrys that have been described as 

 distinct ; and, in addition to the reasons I shall adduce in support 

 of this view, I would call attention to the indirect evidence of 

 its correctness afforded in the errors of identification com- 

 mitted by some of the most acute observers with regard to the 

 forms looked upon as the most persistent and definite. Thus 

 Kolliker mistook A. Eichhornii for A. Sol. Claparede wrote a 

 long paper on A. Eichhornii, and afterwards discovered he had 

 been describing A. Solf. Perty is of opinion that A. Eich- 

 hornii is an enlarged state of A. Sol, whilst Stein also affirms that 

 A. Eichhornii is no other than the lattei' species. I have only to 

 observe on this head, that it would indeed be surprising if the 

 confusion thus created were one whit less than it is, where such 

 characters as the length of the pseudopodia, the diameter of the 



* On the Study of the Foraminifera, p. 18. 



f See Prichard's ' Infusoria,' 4th ed. p. 560, and M. Claparede's paper 

 in the ' Annals,' 2nd ser. vol. xv. pp. 211 and 285. These examples might, 

 however, be multiplied. 



