1865.] DR. H. DOHRN ON THE MOLLUSKS OF THE ZAMBESI. 233 
tura via obliqua, ovalis; peristomium simplex, vie expansum, 
margine collumellari late dilatato. 
Long. +3, diam. 74,5 apert. 7; longa, 7°; poll. lata. _ 
Found in Mozambique, on the mainland, near Cabaceira. 
2. CyCLOSTOMACEA. 
9. CycLosToMUS CALCAREUS, Sowerb. 
Near Tete, and on the Nyassa Lake, commonly in rocky places. 
3. LIMNZACEA. 
10. Paysorsis AFRICANA, Krauss. 
11. Limn#A NATALENSIS, Krauss. 
Both from Lake Nyassa. 
Besides these, there are in the collection two species of Planordis, 
one Limnea, and one Physa which I could not name, but which I 
would not undertake to describe as new, not being sufficiently sup- 
plied with literature on this very difficult family. 
4. AMPULLARIACEA. 
12. LANISTES PURPUREUS, Jonas. 
Mozambique, in a lagoon near Cabageira Grande. 
13. LANISTES OvuM, Peters. 
The Zambesi and Lake Nyassa (unusually large specimens). 
14. Lanisres nyassanvus, Dohrn, sp. nov. 
Testa imperforata, globosa, crassa, olivacea, nitida, striis incre- 
menti sculpta; spira valde depressa, interdum plana ; anfrac- 
tus convexiusculi, interdum ad suturam obtusi angulati, ultimus 
magnus, ventrosus, supra deplanatus, angulatus, tum convexus, 
basi attenuatus ; columella arcuata, callosa ; apertura obovata, 
intus carnea, nitidissima ; operculum castaneum, corneum. 
Diam. maj. 3, min. 22 ; apert. diam. maj. 2, min. 14 poll. 
This large shell was found in considerable numbers near the 
south end of Nyassa, and among the roots of Papyrus near the 
small Lake Pamolombue, through which the Shiré flows after leav- 
ing the great lake. It was not found on the Zambesi or in any 
other locality. 
5. PALUDINACEA. 
15. PALUDINA BULIMOIDES, Oliv. 
River Rovuma. 
16. Patupina porta, Frauenfeld. 
Lake Nyassa. 
I feel inclined to suspect that the Paludina bulimoides has been 
mixed up with the shells from the lake, being the only North- 
African form which I found among them. Should it nevertheless 
