1885 E. R. Lankester in XIX. 841/2 The sclerotia are similar in nature to the hypnocysts of other Protozoa.
1888 G. Rolleston & W. H. Jackson (ed. 2) 258 The [Amœba] when in a state of repose..forms a spherical or oval ball... It sometimes occurs in this condition surrounded by a delicate membrane forming a ‘hypnocyst’. It is then ‘resting’, owing to drought or plentiful nutrition.