MANUAL OF NATUKAL HISTORY. 369 



I. ORDER. ANENTEROUS-INFUSOJEUALS (Anentera). 

 No internal nutritive tube, nor anal orifice. 

 I. SU-OfiDEIt.GmcAKS (Gymnica). 



Body with no external cilia, nor pseudopediform 

 prolongations. 



1. FAMILY. Monads (Monadidse). Without exter- 



nal shell ; body uniform, dividing by simple, 

 spontaneous fissure into two or several in- 

 dividuals. 



2. FAMILY. Shelled -Monads (Cryptomonadidse). 



Individually enveloped in a soft or slightly 

 indurated shell. 



3. FAMILY. Globe-Animalcules (Volvocidse). An 



external envelope or shell, spontaneously 

 dividing into a number of animals which 

 take the form of a polypary. 



4. FAMILY. Thread -Animalcules (Vibrionidse). 



Filiform ; without shell ; associated in fili- 

 form chains by means of imperfect transverse 

 spontaneous division. 



5. FAMILY. Parasitic-Animalcules (Gregarinidse). 



Single, solitary, nucleated cells, without cilia ; 

 parasitic in the intestines of many inverte- 

 brates, especially insects. 



6. FAMILY. Closterians (Closteriidse). Dividing 



spontaneously, into a baciliform polypary; 

 shell with moveable papillae in the aperture. 



7. FAMILY. Astasians (Astasiidse). Body with a 



single aperture, changing at pleasure to 

 caudate, or ecaudate ; shell none. 



B5 



