1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 5ar 
proportion of the food of other birds feeding in the water that their 
capture would appear hardly more than incidental. The gastropods and 
other Mollusca which we found and noted in examining the stomachs 
of birds collected in the Congo were not preserved, as in most cases they 
seemed too badly damaged to serve as specimens for the malacologist, and 
we did not appreciate the interest of securing the scientific names of the 
species eaten. Consequently, we can only list them under very general 
terms, with some mention of the size. 
“In the case of some of the rails it seems Picea whether all 
the snails they had eaten were truly aquatic species, since we know that 
the birds feed only along the margins of watercourses, and often on dry 
land as well. Certain of the rails, on the other hand, are known to feed 
on the land and have been discussed before in connection with the terres- 
trial mollusks. 
“The number of species of birds of which we made rough stomach 
examinations in the Congo is probably about 550. Careful consultation 
of this mass of notes reveals only 40 species where mollusk remains were 
discovered, and in four of these the remains consisted of dead shells or 
bits of shell, which may have been swallowed to aid in triturating the 
food, in lieu of grit or pebbles. Only the following nine species of birds 
may be regarded as having eaten living aquatic mollusks. 
“Anastomus lamelligerus lamelligerus Temminck. Where we did most of our 
work, in the Ituri and Uele districts, the open-bill stork is only a bird of passage 
and not abundant. From present information it seems that the species nests in 
marshes well to the south of the equator, on the Shire, Zambesi, and upper Lualaba 
rivers, toward July and August (the dry season). None have been known to nest in 
the equatorial forest belt, or in the open countries to the north of it, though birds that 
seem to be migrants have been reported in the Sudan from December to May and 
June. Such birds, migrating northward, could profit by the low level of the northern 
rivers at the time of their visit; but many also remain behind upon the breeding 
grounds. 
“ Among our five specimens, only three had food in their stomachs. One had 
extracted the soft parts (feet and gills) of 65 fresh-water mussels, and yet 
had swallowed just one small bit of shell. The other two had been feeding on large 
fresh-water snails of the genus Pila, ten being the largest number in one stomach; 
and while they had avoided swallowing any pieces of shell, they seemed less careful 
about the opercula, of which a few had been ingested. In a specimen collected at 
Kongolo on the Luabala, Mr. H. C. Raven tells me, he found one small snail in the 
stomach with the shell still attached, though bpeelaed: This seemed to be due to its 
small dimensions, the length being only about a half inch. 
“ About Lake Kisale, where this bird is abundant, its food consists very largely, 
according to Dr. Bequaert, of another snail of the family Ampullariide, Lanvzstes 
procerus. Instead of pulling the animal out of its shell with the pincer-like top of the 
