DIG 7 Bulletin American Museum of Natural History [Vol. LIII 
line, so that northwestern Ruanda is excluded from it. The country is 
quite rugged and reaches an altitude of between 1,000 m. and 1,400 m. 
The climate is on the whole tropical, but the distinction between wet and 
dry seasons is very marked. Most of the district is covered with high- 
grass savanna, with very few or no bushes or low trees. Ecological condi- 
tions do not seem very promising to the malacologist, and in fact but little 
has been published thus far concerning the land mollusks of that area. 
The territories of Ruanda and Urundi have been under Belgian 
mandate since 1920 only, so that their fauna was not included in the 
‘Review of Land Mollusks of the Belgian Congo’ published by the senior 
author in 1919.. The only records which we have been able to find in the 
literature refer to the occurrence on the northeastern shore of Lake Tan- 
ganyika of three species of Limicolaria, viz., L. smitht Preston obtained 
by Grauer near Usumbura,! L. martensiana Smith and L. rectistrigata 
Smith, both collected by O. Baumann.? Farther south, beyond the 
border of our territory, many land mollusks have been recorded from 
Ujiji, Ufipa, and Mbwe and it appears probable that most of these will 
eventually be found in Urundi. 
7. Rhodesian Highland District 
This district is chiefly developed in Northern Rhodesia, but it also 
covers the southeastern corner of the Belgian Congo, namely the elevated 
country known as Katanga, on the headwaters of the Lualaba and its 
tributaries. Its northwestern limits are roughly given by a line drawn in 
a general southwest direction from the outlet of the Lukuga to Lake 
Dilolo. They generally follow the 800 m. to 1,000 m. contour-lines, 
being found at a gradually higher altitude as one proceeds from the 
southwest to the northeast. This line is biogeographically of prime im- 
portance since it separates the two main divisions of the Ethiopian | 
Region. Owing to the steep northwestern slopes of the Katanga high- 
lands, it is extraordinarily well defined, the transitional zone being but a 
few kilometers wide. Still, it must be noted that several deep valleys, 
such as those of the Luvua-Luapula, Lufira, Lualaba, and Lubudi 
Rivers, penetrate from the north far down into the heart of Katanga, 
separating a series of high plateaus. Being considerably lower than the 
neighboring country, these valleys still possess a warm, tropical climate 
1See J. Thiele, 1911, ‘Wiss. Ergebn. D. Z. Afr. Exped. (1907-1908),’ EEL p. 203. 
*See R. Sturany, in O. Baumann, 1894, ‘Durch Masgsailand zur Nilquelle,’ pp. 311 and 312. In this 
Cane is also a description of Succinea bauwmanni Sturany, from the sources of the Kagera River 
