Freshwater- Shells from Central Africa. 153 
Hah . Usagara ( Bishop Hannington). 
Of five specimens of this species all have a slender band or 
line at the periphery and another, sometimes a little broader, 
somewhat lower down. They all also exhibit a somewhat 
pellucid or brownish zone around the umbilicus. A line which 
passes round the middle "of the fourth whorl is sometimes 
continued on the fifth and last ; this line in two examples is 
interrupted, thus forming a transverse series of elongate dots. 
A single example is irregularly marked with brown at the 
lower part of the body-whorl and has a second interrupted 
line just above the peripherial zone. The dark scattered 
dots are few and irregular. Owing to the thinness of the 
shell the markings are as vivid within the aperture as upon 
the exterior. There is only the feeblest trace of spiral stria- 
tion. B. nigrilineatus from Madagascar is very like this 
species in form, but exhibits more distinct spiral striation, 
has a narrower perforation, is more numerously banded, its 
general tint more yellow, and not sparsely dotted. B. trutta , 
Blanford, an Indian form, is also very closely related. 
Bulimus (. Rhachis ) quadr icing ulatus. (PI. V. fig. 6.) 
Testa oblonga, subturrita, perforata, tenuis, nitida, flavo-lactea, ad 
apicem purpurea, lineis saturate fuscis (in anfr. ultimo quatuor, 
in superioribus tribus) cincta ; anfr. 6|, perconvexi, regulariter 
sublente acerescentes, incrementi lineis tenuibus obliquis, striisque 
spiralibus confertis exilissimis sculpti, ultimus zona subpellucida 
circa umbilicum, strigisque obliquis paucis subhyalinis hie illic 
ornatus ; peristoma tenue, ad insertionem columellse breviter 
expansum et reflexum ; apertura ovata, longit. totius % paulo 
superans. 
Longit. 12| millim., diam. 7 ; apertura 5| longa, lata. 
Hab. On the plains within 50 miles of Mamboia {Last). 
This is a narrower shell than B. usagarica , differently 
banded, and has a smaller body- whorl and a larger spire in 
proportion to the length of the aperture. Only a single speci- 
men is at hand, and in this, of the three dark zones on the 
penultimate whorl, the uppermost and lowest are quite close 
to their respective sutures, and the intervening band falls 
just above the middle. The three apical whorls are of a rich 
purple-brown colour, which gradually passes into a paler tint 
on the succeeding volution. 
Bulimus ( Cerastus ) mamboiensis. (PI. V. fig. 7.) 
Testa elongata, conica, turrita, subpellucida, albo-cornea vel opal- 
escens, nitida, anguste umbilicata, liris obliquis confertis tenuibus, 
