18 PROTISTS AND DISEASE 



in -ae with " Plantae " understood ; e.g. Rosaceae^ompositae. 

 For cryptogams the ending -ales is also used. 



The word family was first used as equivalent to order ; 

 so by J. H. Balfour (1855), and so in the British Museum 

 ' Handbook of British Lichens,' 1921 ; but in Bennett and 

 Dyer's Sachs (1875) we read " Smaller groups which are 

 called families," and some writers still follow them. 



The class is always a wide group. All the Protozoa are 

 made into only 4 classes : Rhizopoda, Flagellata, Sporozoa, 

 and Ciliata. All the plants fall into 4 great groups : 

 Phanerogamae (flowering plants), Pteridophyta (ferns &c.), 

 Bryophyta (mosses &c.), and Thallophyta (algae, fungi, 

 lichens &c.). The secondary groups of Thallophyta: algae, 

 fungi, lichens, Mycetozoa, &c., constitute each a class. 

 As to the proper term to apply to the next subdivisions sub- 

 class is obvious ; between it and the order groups are 

 variously named ; series (desinence -eae) and sub-series 

 (desinence -ineae) are convenient terms. 



In grouping the protists the Mycetozoa must be given 

 a central position as being about equally animal and vegetable 

 in constitution, and we may arrange on one side of them a 

 series of vegetable, and on the other side a series of animal 

 protists. 



Terminology. The names used for different phases and 

 organs of protists are complicated by some groups being 

 included both in botany and zoology. The well-known 

 Volvox is an alga in botany, a phytoflagellate in zoology. 



