64 MANUAL OF THE MOLLUSCA. 
weed bank, so as to include Madeira, the Azores, and Canary 
Islands.* 
In the Atlantic portion of the province occur the following 
genera, not met with in the Celtic and Boreal seas, although 
two of them, Mitra and Mesalia, occur on the coast of Green- 
land :— 
Argonauta. Cancellaria. Auricula. — 
Philonexis. Sigaretus. Pedipes. Spondylus. 
Chiroteuthis. Crepidula. Ringicula. Avicula. 
— Mesalia. Umbrella. Solemya. 
Conus. Vermetus. Glaucus. Chama. 
Pleurotoma. Fossarus. — Crassatella. 
Marginella. Planaxis. Carinaria. Lithodomus. 
Cymba. Litiopa. Firola. Ungulina. 
Mitra. Truncatella. Atlanta. Galeomma. 
Terebra. Solarium. Oxygyrus. Cardita. 
Columbella. Bifrontia, Cytherea. 
Pisania. Turbo. Cleodora. Petricola. 
Dolium. Monodonta, Cuvieria, Venerupis. 
Cassis. Haliotis. Creseis. Mesodesma,. 
Triton. Gadinia. — Ervilia. 
Ranella. Siphonaria. Megerlia, Panopea. 
Spain and Portugal. 
The coast of Spain and Portugal is less known than any other 
part of the province, but the facilities for exploration are in 
some respects greater than in the Mediterranean, on account of 
the tides. Shell-fish are more in demand as an article of food 
here than with us, and the Lisbon market afforded to Mr. 
M‘Andrew the first indication that the genus Cymba ranged so 
far north. 
On the coasts of the Asturias and Gallicia, especially in Vigo 
Bay, Mr. M‘Andrew obtained, by dredging, 212 species, of a 
* Tn the northern part of the Lusitanian province are the Pilchard fisheries ; in the 
Mediterranean, the Tunny, Coral, and Sponge fisheries. 
The Gulf-weed banks (represented in the map) extend from 19° to 47° in the 
middle of the North Atlantic, covering a space almost seven times greater than the 
area, of France. Columbus, who first met with the sargasso about one hundred miles 
west of the Azores, was apprehensive that his ships would run upon a shoal. (Hum- 
boldt.) The banks are supposed by Professor E. Forbes to indicate an ancient coast- 
line of the Lusitanian land-province, on which the weed originated. Dr. Harvey states 
that species of Sargagsum abound along the shores of tropical countries, but none 
exactly correspond with the Gulf-weed (S. bacciferum). It never produces fructifica- 
tion—the “berries”? being air-vesicles, not fruit—but yet continues to grow and 
flourish in its present situation, being propagated by breakage. It may be an abnormal 
condition of S. vulgare, similar to the varieties of Facus nedosus (Mackayi) and 
F. vesiculosus which often occur in immense strata; the one on muddy sea-shores, the 
other in salt marshes, in which situations they have never been found in fructification, 
(Manual of British Alge, Intr, 16, 17.) 
