ON THE LIFE-HISTORY OF THE FORAMINIFERA. 137 



microspheric form in the reprod\ictive stage which is briefly 

 described in Postscript % at the end of this Paper. 



At the beginning of the process there described, before the 

 protoplasm has emerged from the shell, numbers of nuclei as 

 well as stained strands are present. The nuclei resemble in 

 size and distribution those of a rounded form found in the 

 vegetative phase, but they appear homogeneous, the nucleoli 

 being very indistinct, or altogether absent. In view of the 

 presence of these nuclei in the early reproductive phase, it 

 appears doubtful whether, as above implied, and as stated in 

 the preliminary Paper published in the ' Proc. Koy. Soc.,' vol. 56, 

 p. 156, the whole of the nuclear material becomes distributed 

 through the protoplasm in the previous stage. 



I have no evidence as to the nature of the stained strands, 

 and the part they play in the economy of the organism. I have 

 simply attempted to describe the very remarkable condition 

 which these microspheric forms present.] 



The Megalospheric Form (figs. 13-32).— The Megalo- 

 sphere, which occupies the centre of individuals of this form, is 

 a globular chamber varying considerably in size. Among eighty- 

 nine examples, taken consecutively as they were collected, the 

 diameter of the megalosphere lay between 60 fi and 100/i in 

 seventy cases. The greatest diameter among the eighty-nine 

 cases was 165 fi, and the smallest 35 fi, and this is the smallest 

 megalosphere that I have seen in any example of this species 

 which I have examined. 



The relations of the second and succeeding chambers to the 

 megalosphere are shown- in fig. 13. The second chamber is 

 applied to the megalosphere for its whole length ; at one end it 

 is pointed, and at the other it abuts against the third chamber. 

 The short canal by which it communicates with the megalo- 

 sphere is usually situated near the middle of the concave side. 



Nucleus. — A single large nucleus is present in the great' 

 majority of cases in the megalospheric form. When the nucleus 

 lies completely in one chamber it is usually round or oval. In 

 many cases, however, it is found to send one or more diverticula 



