226 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
and rapid disintegration of the trichogyne, which is a very evanescent 
organ, and is often branched. No fusion of cells takes place in the 
basal region of the cystocarp, as is the case in Gracilaria and other 
allied genera. The fertilised contents of the carpogone are transferred 
through the open pores, connecting the procarpic cells with the support- 
ing thallus-cell, which becomes the central one of the five auxiliary cells. 
Gloiopeltis.* — The late Prof. F. Schmitz has investigated the struc- 
ture of this genus of Florideae, and maintains that the alleged genus 
Endotrichia must be merged in it. G. furcata produces non-sexually 
bodies closely resembling cystocarps in appearance and structure ; while 
G. capillaris bears normal sexual cystocarps. From the form and mode 
of development of the true cystocarps, Gloiopeltis must be placed among 
the Gloiosiphonacese. 
Evolution of the Green Algse.f — Prof. R. Chodat, dissenting from 
many of the views at present current respecting the genetic connection 
with one another of the various families of Chlorophyceae, makes the 
following suggestions : — The principal groups may all be traced back to 
the Palmellaceae, comprising the genera Palmella, Tetraspora , Gloeocystis 
and Apiocystis. The gelatinous general envelope of the Palmellaceae is 
produced by the confluence of the special gelatinous cell- walls. Cell- 
division may take place in three different ways : — irregularly in all direc- 
tions (Palmella-condition) ; in one plane only ( Te^mspora-condition) ; or 
tetrahedrally (Gfasocysfo’s-condition). From these three principal con- 
ditions are derived the three important tendencies which govern the 
lower Chlorophyceae : — (1) The zoospore-condition (Volvocineae) ; (2) the 
sporange-condition (Pleurococcoideae) ; (3) the Tetraspora-st&gQ (Ul- 
vaceae and filamentous green algae). The Volvocinese are derived im- 
mediately from the unicellular species of Chlamydomonas, to which is 
nearly related Gonium, where the tetrasporoid-stage is undergone in a 
motile condition. In Pandorina the earliest stage is the larval condi- 
tion ; Eudorina and Volvox have a very similar origin. In the Proto- 
coccoideae the motionless sporange- stage is the most important. All the 
genera, Oocystis, Nephrocytium, Scenedesmus, Baphidium, &c., can be 
reduced to globular unicellular colonies, which behave like the sporanges- 
of Palmella or Dactylococcus. The Pediastreae, Goelastrum , Sorastrum 9 . 
Pedia strum, Hydrodictyon , &c., constitute a parallel group, arranged in. 
several series. The IJlvaceae and Chaetophoraceae are united with the 
ancestral forms through Monostroma and Pleurococcus. The latter is a 
reduced type, existing as a lichen-gonid, and may develope branched 
filaments, zoosporanges, gametes, or spores. The highest development 
of the filamentous green algae is reached in the Coleochaeteae. 
Reproduction among the Phaeosporeae.f — M. C. Sauvageau points 
out how many lacunae there still are in our knowledge of the different 
modes of propagation, sexual and non-sexual, in this order of Algae. 
Especially Berthold’s observations of the conjugation of the zoospores 
in Ectocarpus siliculosus have not at present been confirmed by any other 
* Trans. Bot. Soc. Edinburgh, xx. (1896) pp. 554-70. 
t Ann. Bot., xi. (1897) pp. 97-121. 
