B02 NATURAL HISTORY SOCIETY OF DUBLIN. 
in A. turfacea, right out through the outer region afar into the water. 
This fringe-like subdivision of the marginal or circumferential portion 
of the outer sarcode-region strongly resembles that characteristic of my 
Heterophrys myriopoda (see my Pl. VIILI., fig. 4). In that form, however, 
there are no spicula. Further, judging from Greef’s figure, his form is 
of a more olive-coloured green than A. turfacea. I do, therefore, venture 
to think this must really be quite distinct. 
Greef, moreover, names a further new form Acanthocystis spinifera, 
of all the described forms, coming nearest to my A. Pertyana, but, 
as will be seen in the remarks following the diagnosis of that species, 
under the head Affinities and Differences, seemingly, indeed, quite a 
different thing therefrom. 
The following will, I think, serve as a diagnosis of the new form 
occurring in this country :— 
Acanthocystis Pertyana (Arch.). 
CEL SEXG fecal): 
Specific Characters—Radial spicula very short, shaft comparatively 
thick, tapering, pointed at the apex; pseudopodia very slender, in length 
about equal to the diameter of the body, bearing minute granules passing 
up and down ; body mostly colourless, but sometimes green when more or 
less loaded with chlorophyll-granules. 
Measurements, variable ; diameter of body from ,35 to dz, length 
of spine zg59 to 33/55 of an inch. ; 
Localities.—In pools near Carrig-mountain, county of Wicklow, 
and in the county Westmeath; rare. 
Affinities and Differences.—This form is readily and at once distin- 
guishable from 4. turfacea (Carter) by its considerably smaller size, 
short, tapering, and pointed spines, of one kind only (not elongate, 
hardly tapering, bifurcate, and of two dimensions). It is likewise far 
more usually devoid of chlorophyll granules than A. turfacea, nor are 
they ever seemingly present in the dense quantity which ordinarily 
characterizes that far more striking species. The pseudopodia do not 
seem to be so delicate in my form, at least they are usually more readily 
noticed than in A. turfacea. 
Its points of difference from Greef’s new species, A. spinifera,* are 
not so manifest at first sight, but on closer comparison the two forms 
are abundantly distinct. ‘That species seems pretty nearly to agree with 
the present in dimensions (though apparently averaging a little larger), 
as well as in the radial spines being slender and pointed ; but in it the 
spines are much longer, far finer, and much more elongate, and more 
* Loc. cit., p. 493, t. XXviL, figs, 20-20 
