50 ] The Classification of Lower Organisms 



this family, and particularly in the genus Gelidium. It is the chief source of agar agar. 

 This is the principal material of the cell walls of Gelidium. It is a jelly consisting 

 essentially of chains of galactose units, and has the property, that having been melted 

 by heat, it does not again become solid until cooled to a much lower temperature. 

 Algae containing it have long been used as foods in the orient. Brought into labora- 

 tory use by Koch, it has become a necessity in routine bacteriological work. The chief 

 source is Japan. 



Kylin construed this order as relatively primitive; but its reproductive processes, 

 involving specialized nurse cells, appear less primitive than those of the Sphaerococ- 

 coidea. The production of elongate connecting filaments is shared with certain 

 examples both of the preceding order and of the following, and the Gelidialea are 

 probably derived by specialization from one or the other. 



Order 4. Furcellariea [Furcellarieae] Greville Alg. Brit. 66 (1830). 



Orders Spongocarpeae and Gastrocarpcae Greville op. cit. 68, 157 (1830). 



Order Epiblasteae Kiitzing Phyc. Gen. 382 (1843). 



Orders Cryptonemeae, Dumontieae, Squamarieae, and Corallineae J. Agardh Sp. 



Alg. 2: 'l55, 346, 385 (1851), 506 (1852). 

 Cryptoneminae Schmitz in Flora 72: 452 (1889). 



Order Cryptonemiales Engler in Engler and Prantl Nat. Pflanzenfam. I Teil, 

 Abt. 2: xi (1897). 



The individuals are crustose or thallose, the thalli cylindrical or flattened, un- 

 branched or branched. On the two or three types of individuals of each species, the 

 reproductive structures may be scattered or clustered on the surfaces or gathered in 

 specialized pits called conceptacles. The eggs are as usual the terminal cells of spe- 

 cialized filaments; other filaments, homologous with these but abortive, bear the 

 auxiliary cells. After fertilization, the zygote may or may not establish connection 

 with a lower cell of the same filaments. Under either circumstance, it sends out fila- 

 ments which establish connection with the auxiliary cells, and these send out filaments 

 which bear the carpospores. In less specialized examples, the filaments growing from 

 the zygote may extend widely through the body; a single one, branching, may reach 

 many auxiliary cells. 



Kylin ( 1932) placed nine families here. 



The family Corallinea [Corallineae] Kiitzing (family Corallinaceae Hauck) is one 

 of the more specialized. The eggs, and subsequently the carpospores, are clustered in 

 conceptacles. In each conceptacle the zygotes, the filaments from them, and the 

 auxiliary cells, unite eventually in a single large multinucleate cell from whose mar- 

 gins grow the filaments which bear the carpospores. Members of this family have the 

 property of accumulating and depositing calcareous material, and were originally 

 classified as corals. In modern usage, the term coral means certain lower animals; 

 but the coralline algae are associated with them in coral reefs, being indeed, accord- 

 ing to Setchell (1926) and other authorities, responsible for the building of the reefs. 

 Fossil coralline algae are known from the Ordovician. 



The parasite Callocolax and its host CallophylUs belong to this order; Coreocolax, 

 belonging to this order, attacks species of order Floridea. 



The Furcellariea are a numerous group, rather unspecialized, varied almost to the 

 extent of a miscellany. They are related to the Sphaerococcoidea, and are believed 

 to represent the ancestry of the two following orders, and possibly also of the 

 Gelidialea. 



