206 NOTES AND MEMORANDA. 



spines furnished with a basal disc, these seated radially on 

 the superficies) ; it gave off no pseudopodia, although the 

 main body-mass sent them off copiously. The author kept 

 this example several days under notice. For forty-eight 

 hours no change was observable, except that the appended 

 portion, wanting pseudopodia, seemed to increase in size. 

 Presently subdivision abruptly set in, and the protoplasm 

 shortly broke up into six portions. These one by one, in 

 the course of an hour, left the inner space formed by the 

 skeleton, this process being begun by their projecting a pro- 

 toplasmic process through the latter, and gradually forcing 

 their way out, and this, indeed, always at the same place. 

 The little body when set free, whilst undergoing amoeboid 

 changes of form, projected at the same time long pseudopodia, 

 passing thus into an actively moving Actinophrys-like body 

 (0-006 mm. in diameter). The author thought he could per- 

 ceive contractile vacuoles and a nucleus therein, but was not 

 able quite to satisfy himself on the point, nor did he like to 

 apply reagents to his only specimen, but unfortunately, 

 after all, these daughter-organisms got lost to observation, 

 without his being able to follow out any further alterations. 

 The Acanthocystis itself had, meantime, thrown off the empty 

 " brood-capsule," without the spicules falling asunder. The 

 whole finally died, after eighty hours' observation, during 

 which, however, the author was unfortunately unable to 

 observe the mode of development of the new nuclei or to 

 throw a light on the part played by the nucleus in reproduc- 

 tion. 



During these efforts, however, he noticed a third mode of 

 development. In a number of individuals he observed 

 within the skeleton roundish or oval corpuscles of about 

 0"01 mm. in diameter, lying in depressions of the surface of 

 the body-mass. These consisted of protoplasm, poor in 

 granules, rich in vacuoles, and in them the author could 

 sometimes detect a nucleus with nucleolus. There were in 

 some cases as many as six of these bodies, but mostly only two, 

 these constantly separated by a bridge of protoplasm. These 

 by and by passed out, the opened system of spicules closing 

 behind them. Mostly no further change could be noticed, 

 but sometimes each developed two flagella, but their languid 

 action only sufficed to slightly roll these little bodies about, 

 and was not great enough to cause them to move off. The 

 author could never succeed in following these up to an 

 Actinophryan stage. In the mean time the interpretation of 

 the purport of these bodies must remain an open question — 

 are they parasitic or reproductive ? In favour of the latter 



