736 MICROSCOPIC FORMS OF ANIMAL LIFE PROTOZOA 



has the curious habit of uniting with neighbouring individuals by the 

 fusion of the pseudopodia, into a common colony,' the individuals 

 sometimes remaining at a distance from one another as at A, but 

 sometimes aggregating themselves into compact masses as at B. The 

 nearly globular thin calcareous shell is prolonged into a short neck 

 having a circular orifico, from which the sarcode-bocly extends itself, 



FK;. 572. Microgroiiiia social is '. A, colony of individuals in extended state, 

 some of them undergoing transverse fission; B, colony of individuals 

 Koine of them separated from the principal mass) in compact state ; C, D, 

 formation and escape of swarm spore, seen free at E. 



giving off very slender pseudopodia which radiate iii all directions. 

 A distinct nucleus can be seen in the deepest part of the cavity; 

 while a contractile vesicle lies imbedded in the sarcodic substance 

 nearer the mouth. Multiplication by duplicative subdivision has 

 been distinctly observed in this tvpe ; but with a peculiar departure 



