1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 493 
obtain forest mollusks alive: it is probable that many of them are noc- 
turnal and should be searched for after dusk. Some could perhaps be 
baited by sugaring the base of trees. ° 
The second-growth forest (Pls. L and LI) occupies the old 
clearings which were made for agricultural purposes and which are 
gradually invaded again by the forest. This reforestation, however, does 
not proceed by the virgin forest coming back at once, but there is an 
_ intermediate stage during which a number of peculiar, rapid-growing trees 
and bushes cover the much impoverished soil. Such second-growth is 
much lower than virgin rain forest and contains fewer species of plants; 
it is more open to the rays of the sun and the soil is therefore much drier. 
Its fauna on the whole is very poor and but few or no land mollusks are 
to be found there. 
Banana plantations in forest clearings (PI. LD on the other hand, 
are likely to well repay the efforts of the collector and this is true also 
of the refuse heaps found near villages. They are about the only places 
in the forest region where molluscan life is at all conspicuous, as in the 
early morning or on rainy days one may see here the large Achatinxe and 
the beautifully colored Limicolarte and Peridertopsis crawl about, often 
in considerable numbers; while Vaginulide and Helixarionine are some- 
times even more abundant. The decaying leaves accumulated at the base 
of the banana stems usually contain in addition species of Homorus, 
Subulina, Pseudopeas, Streptostele, Ledoulxia, and Thapsia; occasionally 
also minute Gulelle and Trochozonites. Many of the mollusks of this 
habitat are widely distributed, being liable to be carried by natives over 
considerable distances in bunches of plantains, in banana leaves used as 
wrapping material, or attached to the shoots with which new cultures 
are started. In a banana field at Kisantu, in the Lower Congo, the 
junior author collected in September, 1910, the following species: Subu- 
lina leia, S. subangulata, Pseudoglessula stuhlmanni, Streptostele alluaudt, 
Ledoulxia rodhaini, and ‘‘Helicarion” sowerbyanus. At Lukolela, in 
October, 1910, Gulella levigata, Subulina perstriata, and Pseudoglessula 
stuhlmanni were found among the decaying leaf-sheaths of banana trunks, 
and Ledoulxia mesogzxa var. nsendweensis occurred in a similar location 
at Ngombe near Irebu. It is undoubtedly in the native plantations that 
malacological collecting may be done with the least effort, but it should 
be remembered that the rare and more local species are only found in 
the virgin rain forest. Another habitat which sometimes teems with 
snails are the low, grass-grown and more or less marshy banks of the 
Congo River, between Stanleyville and Leopoldville. In such a locality, 
