102. PHYLUM PROTOZOA—THE SIMPLEST ANIMALS 
Eighth Type of Protozoa—GREGARINA 
Gregarina, a type of Sporozoa in which the cell is divided 
into two regions by a partition. 
Description.—Various species occur in the intestine of 
the lobster, cockroach, and other Arthropods. When young 
they are intracellular parasites, but later they become free in 
the gut. They feed by absorbing diffusible foodstuffs, such 
Fic. 45.—Life history of Gregarina.—After Biitschli. 
x. Young forms (a, 4, c) emerging from intestinal cells (é.c.);3 .7., 
nucleus of intestinal cell. 
2. Two forms conjugating (G. dlattarum). 
3. Spore formation within a cyst. 
4. Adult with deciduous head-cap (c.c.), and a cuticular partition 
dividing the cell into an anterior part (A) and a posterior part 
(B); ., the nucleus. 
5. A spore within its spore-case (sf.c.). 
as peptones and carbohydrates, from their hosts, and store 
up glycogen within themselves. In many the size is about 
one-tenth of an inch. There is a firm cuticle of ‘“ proto- 
elastin,” which grows inwards so as to divide the cell into 
a larger nucleated posterior region and a smaller anterior 
region, and also, in the young stage, forms a small anterior 
cap. The cell substance is divided into a firmer cortical 
layer and a more fluid central substance. The protoplasm 
often presents a delicate fibrillar appearance, suggesting 
that of striated muscle. The nucleus is very distinct, but 
there are no vacuoles. We may associate the absence of 
