316 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
388 text-figs.). A large and important monograph treating of the 
morphology, physiology, life cycles, development, etc., of this group, and 
giving a detailed systematic classification. The Peridiniales are a mono- 
phyletic group derived from a cryptomonad ancestry. The new genus 
Protodinifer is the simplest form known to us. Starting from it, a line 
of development might lead to Haplodinium, Exuviella, Protocentrum ; 
another such line might lead to the simpler Gymnodiniacese, and branch 
on the one hahd to the higher unarmoured forms (including Pouchetia 
and Erythropsis) and on the other to the thecate forms ( Cercitium ). 
Descriptions of 16 genera and 223 species are given. The new genera 
are Protodinifer , Gyrodinium , Torodinum, Pavillardia , Protopsis , Nema- 
todinium, Proterythropsis. A. Gepp. 
New Kinetic Mechanism. Syndinial Mitosis in the Plasmodial 
Parasitic Peridiniese. — Edouard Chatton ( Gomptes Rendus Acad. 
Sci. Paris , 1921, 173 , 859-62, fig. ; see also Boz. Gaz ., 1922, 73 , 330). 
An account of observations made on species of tSyndinium, which live 
parasitically in the body cavity of Copepods. Their nucleus contains 
but a small number of chromosomes, though previously described 
as ten, ranged like the ribs of an umbrella round one of the poles. 
In reality they are five sharply bent chromosomes, with the apices 
of the sharp angles converging at one pole. Each becomes cloven 
longitudinally. Five of the daughter-chromosomes remain grouped at 
the original pole ; the angles of the remaining five become centred 
about a new pole which gradually moves away from the original pole. 
In some species the cleavage is completed at once ; in others the 
daughter-chromosomes remain united at their tips, and form for a w T hile 
a bipolar spindle-shaped structure. No true achromatic spindle was 
observed. Ordinarily no resting stage occurs. The author gives this 
mitosis a special name, “ syndinial,” and is of opinion that a similar 
form of nuclear division will be found in the free Peridiniese. A. G. 
Classification of Some Colonial Chlamydomonads. — W. Bernard 
Crow ( New Phytologist , 1918, 17 , 3-8, figs.). The name Chlamy- 
domonadales is preferable to that of Volvocales for the order here under 
discussion. The distinctive characters of the families Sphserellaceae 
and Chlamydomonadaceae are displayed in parallel columns. The 
systematic position of Volvox is shown to be with Sphmrellacese rather 
than with the latter family ; it has arisen independently of the other 
known colonial Chlamydomonadales. Gonium , Pandorina and Eudorina 
are colonial members of the true Chlamydomonadacese. Reproductive 
colonies of Pandorina possessing one to four sterile cells have been 
observed. A. G. 
Phylogeny of the Genus Brachiomonas. — Tracy E. Hazen (Bull. 
Torrey Bot. Club , 1922, 49 , 75-92, 2 pis., and figs.). Brachiomonas 
was established in 1898 by Bohlin with two species from Stockholm. 
B. submarina , the type, had been previously discovered by Dangeard 
and by Lagerheim, but not described. It belongs to the Ghlamydomonas 
group, and has a distribution on the coasts of Norway, England, France, 
and Corsica. It w T as found by the author in 1907 near New York, and not 
