BROWN SEAWEEDS OF THE SALT MARSH. 
bc 
-1 
e 
the water being removed by siphons to avoid disturbing the cultures. In 
order to obtain the effect of the spring- and neap-tides the time per diem under 
water was varied according to the following scheme :— 
For 2 days in water 1 hr. in twelve. 
2 » у 2hrs. 
3 " " 3 hrs. - (spring-tide). 
2 ^ " 2 hrs. " 
» 2 »  1hr. " 
3 » 0hrs. „ (neap-tide). 
Frc. 3. 
Fragment of a plant of Pelvetia canaliculata, vay. libera, to show curling of thallus. x 2, 
In this way an equivalent spring- and neap-tide was obtained, each 
recurring once a fortnight, and the working was not complicated 
The cultures may be tabulated as follows. The salts mentioned were added 
to sea-water made up from 37 grms. of Tidman’s Sea Salt per litre. Absorbent 
cotton-wool was used to imitate a surface holding gradually concentrating 
solutions :— 
LINN. JOURN.—BOTANY, VOL. XL, X 
