12 PROTOZOA. 



SPOROZOA. 



GREGARINA. 



Remove the head and posterior end of a larval or adult 

 meal beetle and pull out the digestive tract with a pair of for- 

 ceps. Place the digestive tract on a slide, split it open length- 

 wise with a sharp scalpel, and then spread it out, with the 

 inner wall exposed, and cover. The operation should be per- 

 formed rapidly to prevent the material from drying. If the 

 beetle is infected, numerous gregarines will be visible under the 

 microscope. Study with low and high powers. 



1. Does the animal move? A great number of refractive 

 granules are present in the protoplasm. They are regarded as 

 reserve nourishment. They can be removed with acid. 



2. Note that the body is covered with a membrane, and is 

 divided into a dense superficial layer, the ectoplasm, and a cen- 

 tral, more fluid mass, the endoplasm. 



3. The endoplasm is separated into two parts by a portion 

 of the ectoplasm. The anterior part is termed the protomerite, 

 and the posterior part the deutomerite. In which is the nucleus 



situated ? 



4. Is it possible to distinguish a layer of myonemes just ex- 

 ternal to the endoplasm? 



5. Is there another section of the body just anterior to the 

 protomerite? If so, this is the epimerite. 



6. Note that occasionally two (or more) individuals are 

 united. These aggregations are termed syzygies. 



Before reproduction Gregarina throws off the epimerite, 

 leaves it in the cell-host, and falls into the lumen of the digestive 

 tract. It then encysts, and the protomerite and the deutome- 

 rite form one spore-producing individual. The attached stage 

 in the life-history of Gregarina is termed the cephalont, and the 

 detached stage, the sporont. (Calkins' Protozoa, Fig. 77, and 

 Minchin, Fig. 7.) 



Make a drawing. 



Examine digestive tract of Phascolosoma gouldi for Schizo- 

 cystis sipunculi, an acephaline gregarine. 



