30 



ZOOLOGY. 



already described. This moner-like being, without a 

 nucleus, is the young Gregarina. 



But soon the Amoeba characters arise. The moner-like 

 young (Fig. 18, D E F) no \v undergoes a further change. Its 

 outer portion becomes a thick layer of a brilliant, perfectly 

 homogeneous protoplasm, entirely free from granules, which 

 surrounds the central granular contents of the cytode 

 (Haeckel) or non-nucleated cell. This is the Amceba stage 

 of the young Gregarina, the body, as in the Amoeba, con- 

 sisting of a clear, cortical, and granular 

 medullary or central portion. 



The next step is the appearance of two 

 arm-like projections (Fig. 18, F), com- 

 parable to the pseudopods of an Amceba. 

 One of these arms elongates, and, sepa- 

 rating, forms a perfect Gregarina. Soon 

 afterward the other arm elongates, ab- 

 sorbs the moner-like mass, and also be- 

 comes a perfect Gregarina. This elon- 

 gated stage is c?lled a Pseudofilaria (Fig. 

 18, (?) ; no nucleus has yet appeared. 

 In the next stage Fig. IS, // n, nucleus} 

 the'liimentarj^anai of'a the bodv is shorter and broader, and the 

 teetic, opatr^^jaM,^^ nuclcus appears, while a number of gran- 

 JlJn (a™he heaS""^: "^^^ collect at one end, indicating a 

 t^i.%^fTlX,^\ l^ead. After this the body shortens a 

 «-^n^<:ieus.-Aftcr Gegen- little more (/, J), and then attains the 

 elongated, worm-like form of the adult 

 Gregarina (/i">. Van Bencden thus sums up the phases of 

 gro'wth : 



1. 

 2. 

 3. 

 4. 

 5. 

 6. 



The Moner phase. 



The generating Cytode phase. 



The Pseudofilaria phase. 



The Protoplast (adult Gregarina). 



The encysted Gregarina. 



The sporogony phase (producing zoospores). 



The Gregarina and Amoebaj constitute Haeckel' s group 



