SOME OBSERVATIONS ON ACINETARIA. 387 
Metchnikoff.!. It is also noteworthy that we have here, as in 
the case of many other parasitic animals, e.g. Montstrilla, 
a form the systematic position of which is quite indeter- 
minable from the parasitic stages of its development, but 
which shows quite characteristic features in its later free- 
living stages. Tachyblaston ephelotensis is also of 
interest as showing the beginning of a development of a 
complicated life cycle in association with a parasitic method 
of life in a group of Protozoa which are characteristically 
free living, or, at any rate, purely external parasites. Start- 
ing from the Acinetopsis form, we have free-living tentacle 
buds, which, passing into their host, give rise, by a process 
of division, to ciliated spores of large size, which in turn 
develop on fixation into the Acinetopsis form from which we 
started. 
LIrERATURE. 
Baprant.— Evolution des Microorganismes Parasites,’ ‘C. RK. Acad. de 
Sciences, 27 Aout, 1860. 
Bitscuii, O.—“ Protozoa,” ‘ Bronn’s Thierreich,’ Leipzig, 1889. 
Hickson, S. J.—‘ Acinetaria,” in ‘ Lankester’s Zoology,’ Oxford, 1903. 
Korrpen.—‘ Amoebophrya,” ‘Zool. Anzeig.,’ vol. xvii, 1894. 
Mercunrkorr, E.— Ueber die Gattung Spherophrya,” ‘Archiv fiir Ana- 
tomie und Physiologie,’ 1869. 
NeresHeIMER.—‘ Die Mesozoen,” p. 257, ‘ Zool. Centr.,’ vol. xv, 1908. 
Rozin.—“ Memoire sur la Structure et la reproduction de quelques Infu- 
soires,” ‘Journ. de l’Anat. et de la Phys.,’ 1879. 
Sanp.—‘ Etude Monographique sur le groupe des Infusoires ‘lentaculiferés, 
Bruxelles, 1901. 
Zenker.— Beitrage zur Naturgeschichte der Infusorien,’ ‘Archiv fur 
Mikroscop. Anat.,’ ‘I’. ii, 1866. 
1 The only other parasitic form which has been placed amongst the Acine- 
taria is that curious animal Amoebophrya which occurs in certain Radiolaria. 
Ihave never been able to understand from the published accounts of this 
animal why it was ever placed in this group; and in a recent paper by Nere- 
sheimer in the ‘ Zoologisches Centralblatt’ it is far more appropriately placed 
‘amongst the Mesozoa. 
