PROCEEDINGS OF SOCIETIES. 69 



in place of the flat surface bearing the (as usual in Arcella 

 inverted) aperture being much dilated, as is the case in the ordinary 

 form, by reason of its hemispherical or campanulate figure, in the 

 present form the flat surface was much contracted by reason of 

 its globular figure, hence the tests were prone to roll over and 

 over. Tliis was, moreover, a large form — though, not at any 

 point expanded (like the ordinary form) out of the even globular 

 outline — its diameter was considerably greater than that of D. 

 angulata. In Dr. Wallich's plate of Difllugian forms (' Ann. Nat. 

 Hist.') none, properly referable to Arcella, occur like this. It 

 was not to be mistaken for the so-called Arcella aculeata, nor does 

 Wallich's figure 22 (pi. xvi., loe. cit.), agree with the form now 

 shown, either in form of aperture or in character of test, as that 

 is evidently a built-up test. Pending the rediscovery of this form 

 and further examination, Mr. Archer thought it would be not 

 without advantage that, for sake of reference, it should possess a 

 name, and he would venture therefore to call it, ad interim, Arcella 

 globosa. 



In the same gathering, Mr. Archer pointed out a couple of 

 specimens of the rather common Difflugia sjnralis, which seemed, 

 as it were, to be turning a Closterium lunula to some advantageous 

 account. They were closely attached thereto by the apertures of 

 the tests, and seemed, as it were, to be sucking their prey; the 

 contents of the Closterium were nearly completely eflTete and 

 brown. A similar occurrence appears, indeed, not to be very 

 uncommon. 



Mr. Archer exhibited a form of Aetinophrys, first drawn 

 attention to by Dr. John Barker, and which he likewise had 

 obtained himself in a gathering made from the same locality. 

 This form was minute, colourless, pseudopodia very long and 

 rather slender, but variable in thickness. It was, moreover, 

 remarkable for two seeming specialities, one internal, the other 

 external. The first consisted in the orbicular sarcode mass 

 possessing two well-marked regions — a sharply-defined central 

 body, which was surrounded by shallow margin of a lighter 

 colour and of a " streaky " appearance, with an indefinite 

 outline, whence emanated the pseudopodia. The central portion, 

 occupying by far the greater proportion of the mass, was some- 

 what different in colour and much more dense in structure than 

 the marginal portion, being of that granular appearance and 

 somewhat bluish hue characteristic of the "nucleus" in Amoeba. 



This description calls to mind Stein's Actinoplirys oculata, but, 

 judging from his figures (repeated in ' Pritchard,' pi. xxiii, figs. 24, 

 25), they represent, indeed, quite a different thing. In that form 

 the " nucleus," or eye-like central body giving the specific name, 

 is very small, instead of occupying by far the greater portion of 

 the mass of the body. The character alluded to, however, 

 certainly indicates a resemblance, and in both this central body 

 may be homologous, whatever be its actual nature or function. 

 But the present form is still further unlike by reason of the 



