370 Miscellaneous. 



are completely isolatod in the liquid interposed between the solid 

 contents of the ivst and its wall niovo like the othei-s. 



After tlie lapse of time indicated, tins movement of all the spori- 

 "enons masses ceases snddenly ; eaeh corpuscle returns to a splierical, 

 or nearly spherical, form, and hecomes converted into a detinitivo 

 spore by the production of a thick wall on its surface. In its turn, 

 the voluminous central mass of ijranules on which the spores rest 

 becomes surrounded also with a proper coat, and converted into a 

 vesicle enclosed in the cyst and free at all parts. This pseudoojxt, as 

 I call it, is in my eyes an agent in a new mode of spore-dissemina- 

 tion. By its subsequent growth it presses on the spores compressed 

 between the opposite surfaces of the two s])heres, causes the rupture 

 of the exterior tegument, and conse(iuently the liberation of the 

 reproductive bodies. 



Out of thirty genera that I have examined, the existence of an appa- 

 ratus of dissemination is only met with in the two genera just cited. 

 Genera very nearly allied to Gnyfa-ina or >''>tiflo)-h)jnchus do not offer 

 any trace of the peculiarities whicli characterize these latter ; as, on 

 the other hand, the sporoducts and the ])seudocyst cannot be brought 

 to a common organic expressioji, it is dithcult to decide what value 

 it is necessary to attribute, in the characterization of the Grer/arina- 

 type, to this new element. But it appears certain that this new ele- 

 ment does not create any homology between the Gregarinid'oc and the 

 lower plants. The chemical characters of the walls of the sporo- 

 ducts and of the pseudocyst, as well as the mode of their formation, 

 do not confirm in the least the external analogy that the sporoducts 

 of the Gregarince especially seem to bear at first sight to the emis- 

 sory tubes of the spores of some Chytridiete. — Comptes liendus, 

 February 15, 1875, p. 432. 



Researches into the History of the Bhizopods. 



To the Editors of the Annals and Magazine of Natural History. 

 Gextlemex, — It has been brought to my notice, but only within the 

 present month, that towards the close of last year Professor Leidy 

 pubhshed, in some of the American scientific journals, an account 

 of researches he had made into the history of the freshwater Rhi- 

 zopods, more especially the Amcebce and Difflugirf. 



I am delighted to find that observations, nearly all of which 

 (even to the supposed discovery by Professor Leidy of the very 

 remarkable form for which he has suggested the name Ouramceba) 

 were eml)odied by me in a series of papers, accompanied by illustra- 

 tive figures, which appeared in the 'Annals and Magazine of ^Natural 

 History' in April, May, June, August, November, December 1863, 

 and ifarch 1864, should have been so fully confirmed by such a 

 distinguished writer. It is to be regretted, however, that Professor 

 Leidy should have failed to make any reference whatever to my papers, 

 although I feel satisfied the failure has been a purely unintentional 

 one on his part. I remain. Gentlemen, 



Your most obedient Servant, 

 G. C. Wallich, M.U. 



