GARY N. CALKINS AND RACHEL C. BOWLING. 



.. ,- - and sporoblasts than it is to recognize different 



individuals of the same species of Monocystis. The structure of 

 protoplasm, the nature of the sporocyst capsule, the 



same type of cysts 

 individuals c 

 the agamont 



A-m"; VC. ^AI>-' :; fX,;yW^Wv-^l 

 %p: 



%::. . 



\ x >/;;; *-..-<'. ' .A 



\ fe: : ^M - 2 . .XV>;.A V4-, >-i 



---x ' r- -.- Vj.'&s^s'.v.y v.j ../. , 



-V-.-v'^.^ ;X 



^^**%j-;:: 



s^vf "''' ' 

 \ XI*: ii-i. :--.-t 



FIG. i. Monocystis species. Two gamonts in pseudo-conjugation in sporocyst 

 capsule. Nuclei beginning metamorphosis. Minute spindles in substance of 

 centrosphere. Smear preparation. Camera lucida. X 900. 



appearance of the nuclei in size and character together with the 

 number of chromosomes, are factors involved in the recognition 

 of a cyst of a certain species. We have been no more fortunate 

 than our predecessors in tracing the indisputable connection 

 between a specific agamont and the sporozoites which it ultimately 

 forms and for this reason we beg the question of the particular 

 species of Monocystis with which we are dealing. We are 

 confident however that we have followed the history of one single 

 species. 



We have chosen for particular study the cysts containing the 

 largest sporoblasts and the largest gametes because their nuclei 



