486 Bulletin American Museum of Natural History [Vol. LIII 
(ec) Genera having relatives in Madagascar, the Seychelles, Ceylon, 
Australia, and South America. Family Acavide, comprising all of the 
subfamily Dorcasiine: Dorcasia, Trigonephrus, and Tulbaghinia. The 
“Gondwana” distribution of this family of large helicoid and bulimoid 
snails has been suggested by one of us! and discussed at length by Con- 
nolly?; also by von Ihering* and by Hedley,’ who suggested an Antarctic 
origin for the group. It does not appear likely that existing Acavide are 
survivors of a group formerly living in the northern continents. No 
traces of such distribution have been found in the Tertiary or Mesozoic. 
We have in South Africa, therefore, in addition to the widespread 
Ethiopian genera and their derivatives, a series of forms (Acavide, 
Rhytidide, and Endodontide) which have been regarded as vestiges of a 
Mesozoic Gondwana distribution; afew highly peculiar forms of uncer- 
tain affinities (Celzaxis and Sculptaria); and a group of Pupillide of 
Palearctic affinities.’ 
The island of St. Helena may form a province of the South African 
Subregion. Its chief land mollusks are the genera Chilonopsis (Achatini- 
de), Helenoconcha (Endodontide), Nesopupa and Campolemus (Pupilli- 
dee), and Succinea.® 
Regional Description of the Malacological Land Faun of the 
; : Belgian Congo 
The seven zodgeographic districts of the Belgian Congo (Map 138) 
are further subdivisions of the two main subregions of Equatorial 
Africa. 3 
In the West African Subregion we may distinguish (1) a Guinean 
Forest Province, represented in the Belgian Congo by the LowER GUINEA 
Forest District; and (2) a Guinean Savanna Province represented in 
our territory by (a) the UBanei Savanna District; (0) the SouTHERN 
Conco SavaANNA District; and (c) the UGanpsa-Unyoro SAVANNA 
DISTRICT. 
1Pilsbry, 1911, Rep. Princeton Univ. Exped. Patagonia, III, p. 614. 
*Connolly, 1915, Ann. South African Mus., XIII, p. 122 
5H. von Ihering, 1912, Journ. Ac. Nat. Sci. Philadelphia, XV, p. 491, fig. 2. 
‘Hedley, 1599, Proc: Linn. Soc. New South Wales, XXIV, pp. 396-398. 
’This last group has little significance. Practically all the Pupillide of Africa, Australia, and South 
America are congeneric with or closely related to those of the northern continents. 
In this connection we must call attention to the inaccuracy of J. W. Taylor’s zoogeographic map 
representing helicid distribution (1922, Journ. of Conchology, XVI, p. 288, Pl. x, opposite p. 309), 
reproduced by Hewitt (1923, South African Jl. Sci., XX, p.101). An entirely different map would result 
from plotting the groups according to their occurrence. We do not follow Mr. Taylor in his hypothesis 
that Central Europe has been a great evolution center for the world, though it has been an important 
sl center for certain groups, just as West Africa, the West Indies, and many other places have 
een. 
6See E. A. Smith, 1892, Proc. Zool. Soc. London, pp.258-270. Pilsbry, 1904 ,‘M 1 ? 
XVII, pp. 171-181; 1920, XXV, pp. 363-366. sui aa oe eeoey. 
