188 
G. S. West. 
but although continually on the increase, it did not reach its 
maximum until a full month after the latter species. 
I was quite unable to make the disposition of the plates fit in 
with any described species of the genus, in consequence of which 
I sent drawings of it to Mr. Lemmermann of Bremen. He 
informed me that it appeared to be a new species approaching his 
P. Marssonii 1 , and I have given it the name of P. anglicum. 
Fig. 23. Peridinium anglicum. A, ventral view ; B, dorsal view ; C, epivalve 
(anterior half) ; D, hypovalve (posterior half); E, cyst within old wall; F, 
escaped cyst; G and H, division of cyst; I, escape of an elongated cyst from 
old wall; J, escape of motile individual from cyst; K and L, divisions of thin- 
walled motile state. All x 500. 
In Fig. 23 C, I—VII. are the equatorial plates ; r, the rhomboidal plate ; va, 
the ventral anterior (or ventral apical) plate ; da l and da t , the dorsal anterior 
(or dorsal apical) plates. 
About the time of its maximum abundance, P. anglicum 
multiplies very rapidly by the production of thin-walled cysts. 
1 Lemmermann in Ber. Deutsch. Botan. Ges. XVIII., 1900, p. 28. 
