")<) JJKITISH FBESmVATKK, HELIOZOA. 



4. Acanthocystis brevicirrhis (Perty). 

 (Plate LXIV, fig. 4, LXIX, fig. 1.) 



Actinophrys brr c ic/rrJi is 



PERTY Zur Kennt. klein. Lebensformen, 1852, p. 159, pi. viii, f. 7. 

 Acanthocystis ]>< rt ijuna 



ARCHER Qrt. Jrn. Micr. Sci. (N.S.) IX, 1869, p. 252, pi. xvi. f. 1 ; non 



PENARD Heliozoaires, 1904, p. 248, tig. 

 Acanthocystis paludosa 



WEST J. Linn. Soc. Zool. XXVIII, 1901, p. 340, pi. xxx, if. 32, 33. 

 Acanthocystis / 



LEIDY Rep. U.S. G-eol. Surv. XII, 1879, p. 270, pi. xliii, ff. 14-16. 



Body of medium size, spherical, having a double 

 outer investment, the inner portion consisting of a 

 thin layer of small silicious scales, the outer portion 

 consisting of numerous, short, pin- or thorn-like spines 

 attached by their enlarged bases either radially or 

 divergently; plasma colourless or greyish, often con- 

 tnining numerous green chlorophyll cells, also numerous 

 granules and food particles ; endoplasm not clearly 

 differentiated, placed eccentrically, containing a central 

 granule; nucleus single, grey in colour, placed eccen- 

 trically, usually concealed from view by the plasma 

 and its contents; contractile vesicle single, large; 

 pseudopodia long, tenuous, granuliferous. 



Diameter of envelope without the spines 30 /x, to 

 about 50 /x, (Penard 18 /JL to 40 ju,). Length of spines 

 //,. 



Lakes, ponds, ditches and quiet parts of 

 rivers and streams. 



Distribution. ENGLAND.- Shelf and llkley (G. 8. 

 HV.s) ; Sheffield District (l>r<nni); W. Yorkshire; 

 Derbyshire (Brown); Hornsea Mere, Lincolnshire; 

 Thames at Weybridge, Surrey. 



SCOTLAND. Aberfoyle ; Craigcaffie ; Ben Ledi ; Pt. 

 Patrick (Itroirn.). 



IRELAND. Carrig Mt., Wicklow (Archer). 



5 x to 1 



