154 J. J. LISTER. 



nuclei are very often disposed in pairs in the protoplasm, and in 

 some cases the pairs may be seen to be united by a constricted 

 band, being killed in process of division (fig. 41). The nucleoli 

 in such dividing nuclei are as distinctly seen as in those which 

 are single. 



There appear to be all intermediate forms between the 

 small nuclei and the larger ones. In the latter the reticulum 

 is more clearly seen, and the nucleoli are less conspicuous. 

 They are, moreover, not disposed in pairs, but solitary (fig. 42). 



There are generally numbers of stained particles present in 

 the protoplasm, some of which appear to be food material. It is 

 possible that others may be of nuclear nature, but I have not 

 recognised in these specimens anything of the nature of the 

 stained strands met with in the microspheric form of Poly- 

 stomella. 



Reproductive Phase. — I have met with thirteen specimens 

 among my preserved material, in which the brood chambers 

 contained young. In those which have been decalcified (seven), 

 the part of the disc internal to the brood chambers contained 

 no protoplasm. It is clear that the protoplasm has been with- 

 drawn from the small chambers of the disc and massed in the 

 brood chambers, where it has been divided up into the young. 

 In such specimens this central part is quite transparent, and 

 consists of the organic basis of the walls of the chambers, 

 together with the larger parasitic algae which are contained in 

 them (fig. 43). 



In marked contrast to the central region are the brood 

 chambers at the periphery, closely packed with the young (figs. 

 43 and 44). In all my specimens the young are fully developed, 

 and in all they belong to the megalospheric form. They consist 

 of the primordial and circumambient chambers, invested by the 

 darkly staining basis of the thin shell, from which the calcareous 

 salts have been dissolved. The protoplasm of the primordial 

 chamber is generally denser, and takes a darker stain than that 

 in the circumambient chamber, and an oval nucleus measuring 

 about 20 X 15 /u. lies in it. Even in this young condition the 

 small parasitic algse are present in the protoplasm. 



