148 NOTES ON RANGE IN DEPTH OF MARINE ALG. 
Mentha hirsuta, b. subglabra, Baker. Leonurus Cardiaca, Linn. 
M. sativa, 6. paludosa, Sol. Carduus Forsteri, pha 
Ballota ruderalis, Fries (the true Same rostellata, L 
plant). nopodium rte, 255 
Excluded Species. 
Erysimum orientale, Br. Waste Rosa pomifera, Hern. Coppice 
e near the docks, Glou- wood, near Painswick. 
Achillea nobilis, Zinn. Waste 
Malls parviflora, Lam. Banks ground, near the docks. — 
of the el opposite the docks, pen. centaurioides, Linn. 
Glouceste Banks of the enini near the 
din. 
NOTES ON RANGE IN DEPTH OF MARINE ALGÆ. 
By Prorsessor DICKIE. 
(Read to the Botanical Society of Edinburgh ; Revised by the Author.) 
The bathymetrical range of animal life has been of late attracting a 
due share of attention, and facts of great interest have been ascertained. 
Very little has been done regarding the range in depth of marine plants ; 
few instances have been recorded, and even some of these are not quite 
trustworthy. 
When the dredge ceases to scrape the bottom, it becomes in its pro- 
gress to the surface much the same as a towing-net, capturing bodies 
which are being carried along by currents, and therefore great caution 
is necessary in reference to any marine plants found in it. Seaweeds 
are among the most common of all bodies carried by currents near 
the surface or at various depths below, and from their nature are very 
likely to be entangled and brought up. 
The present communication is offered chiefly with the view of di- 
recting attention to the subject, and of recording a few facts, which 
may, perhaps, stimulate algologists to add to the number of such. 
There are two effects which diminished supply of light at great 
depths may be expected to produce upon Zf/gz,— decrease of size and 
modification of colour. The proportion of light necessary for the ger- 
mination of the spores, and subsequent development, surely deserves 
the attention of physiologists.* 
2n Reb of Natural History, Dec. 1868, there are some remarks by 
Mr. Jeffreys regarding various Mollusea, ri bright- ^ie Mil and well- 
developed eyes, at depths from 200 to more than 1500 fathom 
M m 
