82 



PROTOZOA 



night, and when stimulated, these bodies are luminescent, giving to the 

 water a pervading greenish white or bluish white light. 



108. Sarcodina. — Sareodina (Fig. 28) include not only the ameba but 

 also many other similar forms, some of which are parasitic. A number 

 of them secrete an external shell of chitin, cellulose, lime, or silica, or 



Paras/fes 

 Parasife. 



Nucleus of 

 corpuscle 



^m 



K);' 



Parasites 



Fig. 29. — Examples of Sporozoa. A, a hemogregarine in the red blood corpuscle of a 

 frog. (From Hegner and Taliaferro, "Human Protozoology .'') X 550. B, section through 

 the intestinal epithelium of a rabbit, showing infection with one of the Coccidia, Eimeria 

 stiedae (Lindemann). {From Doflein, ''Lehrbiich der Protozoenkunde," after Thoma.) 

 Highly magnified. C, Gregarina hlattarum Siebold, from the digestive tract of the cock- 

 roach. {From Doflein, after Hertwig.) X 60. Shows an endwise union of two individuals, 

 a union which occurs commonly and is known as syzygy. D, section through the intes- 

 tinal wall of a meal worm (the larva of a beetle), infected with Gregarina polymorpha (Ham- 

 merschmidt). {Also from Doflein, after Pfeiffer.) Highly magnified. Immature parasites 

 in different stages of development are seen in the epithelium lining the intestine and one 

 mature individual in the lumen of the canal. {A by the courtesy of The Macmillan Company; 

 B, C, and D by that of Gustav Fischer.) 



they build one of particles of sand and other foreign objects held together 

 by one of these substances. 



Interesting members of this class are the Foraminifera, which are 

 mostly marine and which form shells of lime composed of numerous 

 chambers united by openings called foramina, whence the name of the 

 group. They occur in enormous numbers and exhibit great variety. 

 When the shells of dead individuals sink to the sea bottom they form a 

 soft mud or ooze, known as foraminiferous or Globigerina ooze, which, 

 when solidified, becomes natural chalk. 



