388 BOTANICAL GAZETTE [JUNE 
those of cells seen in the surface-view of each antheridum. The 
actual number of cells in each antheridium is much greater. These 
show as follows: 
BEAUFORT BANGOR 
pst Gaye ese Undivided rudiments Undivided rudiments 
Coe) eee 8-16 cells a fe 
UN Gayo. 55. on cells - al 
RPA ORY. 2s wars cells my tee 
OU Gayen os ws alas libera 
ath cavers: Liberation se honed sori 2-4 cells 
roth day....... Many 6 wt 
$ath day... General li 
Es Gay oss. Liberation ie baat sori. 
In addition to this difference is the fact that the records taken 
make it probable that every crop produced during the fruiting season 
at Beaufort was similar in development to the one described, while 
at Bangor there is considerable difference in the development of 
different crops. The cause of these differences in the fruiting of 
the plants on our coast and on the coasts of Wales and England is 
not apparent. A comparison of thé tides at the different localities, 
however, is of interest in this connection (6) (charts 1 and 2). 
The average range of the tide is: near Bangor, Wales, 17-9 
feet; at Plymouth, England, 11.5 feet; at Beaufort, N. C., 2.8 feet. 
The average difference in the height of low water at spring and neap 
tides is: near Bangor, Wales, about 5.7 feet; at Plymouth, England, 
about 3.4 feet; at Beaufort, N. C., o. 5 foot. We are still unable to 
say whether these differences will explain the difference in behavior, or 
whether this is due to some other, possibly ancestral, cause. 
It is possible that the Dictyota occurring at Beaufort is a different 
species from that found at Bangor or Plymouth. To determine this, 
a specimen was sent to Mr. FRANK S. Coxtins of Malden, Massachu- 
setts, who verified the identification, referring it to D. dichotoma. In 
spite of the morphological resemblance, however, it is possible that 
the Beaufort form is a different physiological species, and this can be 
determined only by means of cultures. The final test can be made only 
by growing some of the Bangor plants at Beaufort and vice versa. 
It is hoped that this can be done at some future time. 
The explanation of this periodicity is not apparent. Although the 
