DR. G. DICKIE ON ST.- HELENA MARINE ALGEX. 179 
States, Mediterranean, West Indies, Red Sea, Indian Ocean, 
Cape of Good Hope, Mauritius, Australia, New Zealand. 
II. RHODOSPERMEZ. 
Family LAURENCIACE X. 
Laurencia cruciata, Harv. 
Geographical Distribution :— Western Australia. 
This species is very near Z. obtusa, Lamx., which is widely 
diffused in both hemispheres. 
Family CORALLINACEZ. 
Corallina carinata, Ktz. 
Geographical Distribution :—Cape of Good Hope. 
Amphiroa fragilissima, Lamx. 
Geographical Distribution:—Cuba, Eastern India, Mediter- 
ranean, 
A, exilis, Harv. ? 
In such fragmentary condition, that I mark it as rather 
doubtful. 
Geographical Distribution :—Cape, Brazil, Mediterranean. 
Lithothamnion crassum, Philippi. 
Geographical Distribution :—Mediterranean. 
L. brassica-florida, Harv. 
Geographical Distribution :—Algoa Bay. 
Examination of specimens from Algoa Bay leads me to con- 
clude that these two species are most probably forms of one. 
Melobesia farinosa, Lamx. 
Geographical Distribution:—Very generally in both hemi- 
spheres, 
Family GELIDIACEZ. 
Pterocladia lucida, Br. : ; 
The specimens are very dwarf, about an inch in height, 
cespitose, and varying in ramification. The presence of a nerve at 
the base, minute structure, &c. leave no doubt as to the genus 
and species; it is, however, very unlike the luxuriant forms from 
Australia; the late Prof. Harvey considered the plant to be 
quite as variable as Gelidium corneum. 
N 2 
