THE FORAMINIFERA 125 



approximation of the megalosphere to the size of the microsphere. 

 Thus in 13 examples I found 12 to be megalospheric and 

 the value of M to be, on an average, 28 /*, varying from 36 

 to 1 5 p. The other specimen is microspheric, and m = 1 1 p.. 

 The nuclear characters corresponded to those described in Poly- 

 stomella (20). 



Plastogamy. This remarkable and little understood process 

 which has been observed in other groups of Protozoa was found 

 by Schaudinn to be frequently associated with the reproduction of 

 Patellina and Discorbina. In the former the pseudopodia of two in- 



FIG. 53. 



View from the under side of two specimens of Patellina corrugata, Will., which have united 

 in plastogamy prior to the breaking-up of the united protoplasm to form a brood of young. 

 1, young of varying size ; 2, nucleus of a young individual ; 3, accumulations of detritus. 

 (After Schaudinn, 45.) 



dividuals that have come, apparently by chance, into juxtaposition 

 fuse, and form a uniting band which increases in thickness until 

 all' the extruded protoplasm is involved in it, and the tests are 

 drawn close together. The nucleus in each meanwhile divides in 

 the manner above described. Gradually the protoplasm of both 

 emerges into the space between the bases of the approximated 

 tests and the surface to which they are attached, and then, as in 

 the reproduction of a single individual, divides up about the nuclei 

 to form a brood of young (Fig. 53). As many as five individuals 

 may thus unite. In no case did Schaudinn observe any fusion 

 between the original nuclei or the fragments into which they 

 divided. He also found that the process only occurred when the 

 nuclei of the individuals which met were in the same phase of 



