196 MARIE V. LEBOUR. 
(52) Spirodinium glaucum n. sp. (Fig. 13). This is a very common 
species, perhaps the commonest Spirodinium in this area. 
It begins in May, having its maximum in May and June 
and persists till October. A large yellow body posteriorly is 
characteristic, although this may be absent in young forms and 
Fic. 13.—Spirodinium glaucum n. sp. x 466. 
a ventral view, b dorsal view, c—f division stages. N—=nucleus. 
possibly is only food remains, although it is always the same 
colour and in the same place. These yellow bodies are also some- 
times absent in divisional stages. The body is elongated with 
a long anterior and short posterior portion, with a few wide 
apart longitudinal striz. Transverse furrow with the ends wide 
apart ; longitudinal furrow short and with the appearance of a 
