241] STUDIES ON GREGARINES WATSON 31 



The endoplasmic content of the protomerite and deutomerite differ 

 more in density than in character of the granules. The protomerite con- 

 tains homogeneous granules about the same size and consistency as those 

 of the deutomerite but fewer in number, rendering this portion always 

 less dense. 



Myonemes are difficult to detect in the Gregarinidae, even with an 

 oil immersion objective, when the animals are alive. They can be seen 

 in longitudinal sections of adults as large deeply stained dots seemingly 

 larger protoplasmic granules, situated at the edge of the endoplasm (Fig. 

 232). Cross sections naturally do not reveal their presence. In total 

 mounts and with an intravitam stain they can be seen as a delicate net- 

 work of fibrillae extending around the animal (Fig. 243). 



Longitudinal striations in the epicyte are rendered visible by sim- 

 ply crushing the animal on the slide and liberating the dense endocyte. 

 They are very delicate parallel striations visible with the oil immersion 

 lens and situated on the outside of the epicyte. They may be seen in 

 both protomerite and deutomerite and traced continuously from one end 

 of the animal to the other (Fig. 243). They do not converge at the ante- 

 rior and posterior ends, being continuous over the ends as at other parts 

 of the body. The writer has never seen between the striations the pores 

 which Schewiakoff says serve for the extrusion of the mucus. 



The nucleus in the genus Gregarina is always spherical. In the tro- 

 phozoites and in immature sporonts there is often but one large karyo- 

 some and never more than five or six. As the size of the animal increases, 

 the karyosomes increase in number and decrease in size and are scattered 

 irregularly throughout the nucleus. In mature sporonts they are often 

 arranged in a twisted chaplet and are then too numerous to count. One 

 of the reasons why maturity of the cyst and its dehiscence in the Grega- 

 rinidae occupies so short a time (two days) may be that the nucleus of 

 the mature sporonts has already broken up into numerous small ele- 

 ments before cyst formation has taken place and only needs to lose its 

 wall while in the cyst for these particles to surround themselves with a 

 portion of the sporont endoplasm and becomes gametes. In the Steno- 

 phoridae, the nucleus of a mature sporont contains but one large karyo- 

 some which after cyst formation has taken place must break up into con- 

 stituent elements. 



The epimerite of all the Gregarinidae in which it has been observed 

 is a large globular slightly stalked or sessile structure which is often re- 

 tained after its usefulness is gone and the trophozoite is liberated in the 

 lumen (Figs. 224 to 227). There is little endoplasm present in the nearly 

 transparent epimerite which can be demonstrated with an intravitam 

 stain. 



