146 SEAWEEDS 
joined to Acctabularia, and these are characterised 
by the radiating chambers being free from each 
other, and by other differences. 
The best studied species is 4. mediterranea, and a 
Fic. 43.—a, Acetabularia exigua decalcified (magnified) ; b, Acicularia Mubti, 
longitudinal section with two superposed caps; ec, Acetabularia Calyculus, 
cap-ray with spores showing upper and lower corone; d, A. exigua, spores 
with lid. b, c, d highly magnified. (After Solms-Laubach.) 
description of it will enable us to understand the 
variations displayed by the others. It has an erect 
stalk six to nine centimeters high, with a cap about 
a centimeter across, strongly calcified and_parti- 
tioned into a number of regular radial chambers, 
