63 
shore out into the sea, consisted chiefly of Lithothanmion erubes- 
cens f. Haingsisiana. It was remarkable that the aries 
knolls remained quite dry during several hours of the day, ex- 
posed to the ae of the tropical sun and that this a not 
to injure them. . . . This Lithothamnion-bank struck me be- 
cause it is such a unique sight to see the ground, as far as the 
eye can reach, covered by the pretty beautifully pink-coloured 
knolls, which are heaped up so close together that, while walk- 
ing, one crushes them continually, making a peculiar noise as of 
broken china. We encountered, however, other and Perhaps 
more instructive Lithothamnion-banks during our voyage. 
It seems evident that the building-up of the so-called coral- 
reefs and coral-islands, which, in semipopular scientific literature 
has been ascribed almost exclusively to animal agencies, is, in 
many cases, at least, due in an important part to these calcareous 
plants. For reasons that are obvious, the collection of coralline 
algae has been much neglected by the general botanical explorer, 
and even those who make a specialty of collecting marine algae 
are likely to pass some of them by unless prepared for detaching 
crustaceous species from the rocks and equipped for transporting 
heavy loads. Consequently, the coralline seaweeds, particularly 
those of the tropical regions, are still quite imperfectly known. 
I be remarked, in passing, that the living color of the 
corallines in general is some shade of pink or red, but most of 
them become decolorate or chalky white very soon after being 
taken from the water and exposed to the light, or after the natural 
death of the plant. Some of the crustaceous and fruticulose 
. ae beginning life attached to shells, rocks, corals, 
nally me free and lie loose on the sea-bottom. Some 
a these ena pieces may be ene over by the waves often 
enough so that they develop in a globose, radially symmetrical 
” 
orm 
The group of corallines which has very properly inherited the 
ancient generic name oo is represented on our American 
North Atlantic coast only by what is probably a single vari- 
able species, Corallina eee The corallines in this nar- 
rower sense have a regularly cones plant-body and are very 
