CHLOROPHYCEA 149 
above each other (Fig. 44). Halicoryne is, in fact, a 
better representative of the Acetabulariew than the 
dise-forming Acetabularia, since it supplies us with a 
link to the other Dasycladacee, from which it is distin- 
guished, however, by the alternation of fertile and 
Fic. 44.—Acetabularia crenulata with several caps in longitudinal section 
highly magnified. (After Solms-Laubach.) 
sterile whorls, in addition to the more important 
characters of the sporangia. The genus Chalmasia 
(like the former genus Polyphysa) has no corona in- 
ferior, and while closely resembling Acetabularia in 
most respects, agrees completely with Halicoryne in 
the structure of the spores. In Halicoryne their mem- 
