424 



PHOF. ALLMAN ON THE EECENT BESEAECHE8 



cation by transverse fission. When this is about to take place 

 the posterior or nou-flagellate end becomes blunt and rounded, 

 and the monad assumes a semiamoeboid condition, the sarcode be- 

 coming irregular in outline (B). The common root of the flagella 

 now splits, so that the four flagella are separated into two pairs, 

 which recede more and more from one another until finally we 

 find them situated on two diametrically opposite points of the 



Fig. 13. 



Development of " Calycine Monad." 

 A, fully developed monad, with nucleus and contractile vacuoles and four 

 flagella. B, the monad in the semiamceboid state which precedes fission. C, the 

 monad in the act of spontaneous fission. D, one of the two segments resulting 

 from fission, each of the two flagella becoming doubled by longitudinal split- 

 ting. E, the amoeboid condition which precedes fusion. P, two amoeboid 

 monads in the act of becoming fused into one another. H, the two blended bodies 

 enclosed in a sac which is pouring out a cloud of sporules. J, I, Q, thesporules 

 becoming developed into the parent form. (After Dallinger and Drysdale.) 



