306 W. ARCHER. 



substance, in which the balls were imbedded, gradually 

 disappeared. Schneider afterwards^ confirmed this observa- 

 tion, carrying the observation on to the development of 

 young Actinosphseria ; but this observer saw formed around 

 so many pairs of balls, each of which contained eight to ten 

 nuclei (of the same kind as the fully-grown Actinosphserium), 

 a firm elliptic cyst, within which again each ball of each pair 

 acquired an outwardly rough, inwardly smooth, thick-walled, 

 special cyst, the common outer cyst bursting by and by. The 

 thick Avail of the inner cysts, according to Schneider, was 

 composed of numerous siliceous pieces, having between them 

 little lacunae. From July to December these remained un- 

 changed ; they then showed the numerous nuclei had disap- 

 peared, and in the middle of each only one nucleus with 

 nucleolus. Up to the beginning of May they remained in 

 this condition ; the walls of the cysts then burst, and there 

 came forth a little Actinospliserium with a number of 

 nuclei. The previous disappearance of the numerous (eight 

 to ten) nuclei and the subsequent presence of only one was 

 explained by Schneider as due to fusion thereof; and he 

 attributed thereto the character of an act of fertilisation ; 

 hence he conceives that from the "ovum" (Ei) enclosed 

 in the siliceous cyst, proceeds, by a process of cleavage of 

 its before single nucleus, a young multi-nucleated animal; 

 this grows and feeds and again copulates with other in- 

 dividuals, the special sexual act being the conjugation of 

 the nuclei, whence proceeds the ovum-cell capable of 

 development. 



Greefi" likewise suggests, as only very probable, a forma- 

 tion of embryos taking origin from the numerous nuclei 

 of the '^central capsule." He saw proceed from a great 

 number of dead Actinosphseria a very large number of very 

 minute Amoebae, each with a nucleus and a contractile space, 

 after the disappearance of which several little vacuoles 

 appeared in lieu. These Amoebae shortly passed into a resting 

 state, assuming a globular or pyriform figure ; these after- 

 wards became changed into a flagellate zoospore. 



Schulze's own observations agree generally with those of 

 Cienkowski and Schneider, though diifering from the latter 

 in some points. 



The pseudopodia became shortened and eventually 

 wholly retracted, their axile threads becoming less distinct 

 and gradually disappearing (proving surely it is not a "spine"), 

 their cortical layer becoming drawn into the alveolar paren- 



1 Schneider : ' ' Zur Kenntniss der Radiolarien," ia ' Zeitschr. fiir Wiss. 

 Zool./ Bd. xxi, p. 507. 



