478 Davis.- — The Origin of the Archegonium. 
which have advanced to the level of sexual evolution termed 
heterogamy. 
The sexual elements of heterogamous Algae are almost 
universally formed in single cells. These cells are generally 
called oogonia when they contain eggs, and antheridia if they 
produce antherozoids or sperms. Sometimes a collection of 
sperm-producing cells, with or without accompanying sterile 
tissue, is called an antheridium. This term has therefore 
ceased to have exact morphological value, and is applied to 
structures widely different in their degree of complexity, 
some being unicellular and some multicellular. 
This vagueness in terminology has led to a recent protest 
by Vuillemin 1 , especially with reference to the term ‘sporan- 
gium,’ which is now applied to any organ bearing spores, re- 
gardless of its structure, whether multicellular or unicellular. 
Vuillemin suggests a terminology that will clearly show the 
morphology of the reproductive organs of Thallophytes 
in contrast to conditions among the higher plants. He 
proposes the following names for unicellular reproductive 
organs : — 
Sporocyst, an unicellular structure, producing asexual spores. 
Gametocyst, „ „ „ gametes. 
Oocyst, „ „ developing eggs. 
Antherocyst, „ „ „ antherozoids 
or sperms. 
These unicellular structures may then all be removed from 
the group of multicellular reproductive organs, which will 
then retain the old terms of — 
Sporangium, a multicellular organ, producing spores. 
Gametangium, „ „ „ gametes. 
Archegonium, „ „ peculiar to higher plants, 
developing eggs. 
Antheridium, „ „ developing antherozoids 
or sperms. 
The question of terminology may seem to some a minor 
1 Vuillemin, Bull. d. 1 . Soc. Bot. d. France, xlix, 16, 1902. 
