THE PERIDINIALES OF PLYMOUTH SOUND. 197 
three-cornered bite having been taken out of the posterior end. 
This species is rather like G. teredo, with the exception of the 
chromatophores which are numerous in the latter species. Cell 
colourless except for the yellow mass. Nucleus in the region of 
the transverse furrow. Divisional stages are often seen in the 
free state, one individual pushing part of its body backward so 
that a chain of two is formed very much like the figure given by 
Pouchet of the division of S. spirale (loc. cit.). Earlier stages in 
division show that the longitudinal flagellum persists as is described 
by Dogiel in his Gymnodinium spirale v. obtusum. A growth 
then takes place at the side of the whole body, so that the cell is 
very much swollen transversely ; then division takes place, begin- 
ning at the posterior end as a groove and half the cell is pushed 
backwards so that the chain of two individuals is formed, one 
attached to the side of the posterior end of its fellow by its extreme 
anterior end. After division the individuals are small and may 
Fia. 14.—Cochlodinium pulchellum n. sp. X 466. 
or may not contain yellow bodies. In one case the yellow body 
appeared to be dividing at the same time as the cell, which perhaps 
shows it to be a chromatophore. 
Genus CocHLODINIUM Schiitt. 
(53) N.R. Cochlodinium helix (Pouchet). Occurs occasionally in the 
water samples in August, sometimes free, sometimes enclosed 
in a spacious perfectly transparent covering. 
(54) N.R. Cochlodinium pellucidum Lohmann. Rare. In the water 
samples in July and August. 
(55) Cochlodinium pulchellum un. sp. (Fig. 14). This species was 
found once only in the water samples from 7 fathoms, August, 
1915. It is perfectly colourless and contained in a roomy trans- 
NEW SERIES.—VOL. XI. NO. 2. MAY, 1917. (0) 
