CAPE REGION. 97 
continents than now maintains is dimly indicated. The infor- 
mation we have obtained respecting the extinct and existing 
terrestrial mollusks would seem to point in the same direction, 
and assuredly to indicate a closer geographical alliance between 
St. Helena and the east coast of 8. America than now holds.” 
(Forbes.) 
Tristan @ Acunha (No. 29 of Map). 
Two peculiar species of Balea (Tristensis and ventricosus) are 
found on this remote and lofty island, which attains an eleya- 
tion of 8,236 feet. 
3. AFRICAN REGION. 
Tropical western Africa, with its hot swampy coasts and river 
yalleys is the region of the great Achatine and Achatina-lke 
Bulimi, the largest of all living land-snails. In 1863 the 
numbers known were—Vitrina 4 sp., Streptawxis 7, Helix 30, 
Pupa 5, Bulimus 50, Achatina 54, Succinea 3, and Perideris 18. 
Streptaxis Recluziana inhabits the Guinea Islands. Helix Folint, 
Bulimus numidicus and fastigiatus, Pupa crystallum and sorghum, 
Achatina columna, striatella, and lotophaga are found on Princes 
Island ; Pupa putilla on Goree Island ; Bulimus (Pseudachatina) 
Downesi, Achatina iostoma and Glandina cerea at Fernando Po. 
The reyersed river-snail (Zanistes) is generally diffused in the 
fresh waters of Africa; several species of Potamides and Vibex 
are found in the embouchures of the western rivers and Pedipes 
on the sea-shore. The fresh-water bivalves of Senegal are 
similar to those of the Nile :— 
Pisidium parasiticum, Egypt. Iridina exotica, Senegal, 
Cyrenoides Duponti, Senegal. 6 rubens a 
Corbicula, 4 sp. Egypt. Pleiodon ovatus or 
Tridina nilotica a fitheria semilunata ,, Nile. 
a aegyptiaca Galatea radiata a 
4, CAPE REGION. 
Dr. Krauss describes 41 species of land-snail from South 
Africa, and Mr. Benson has furnished a list containing 22 
others; these are all peculiar, except a Succinea, which appears 
to be only a variety of the European S. putris, and two Euro- 
pean Helices (H. cellaria and pulchella) probably imported to the 
environs of the Cape. In 1863 they had raised the number to 
about 90. There are also 8 slugs, 9 freshwater Pulmonifera, 4 
marine Pulmonifera, 5 freshwater bivalves, and 5 univalyes 
P 
