1882. ] MOLLUSCAN FAUNA OF MADAGASCAR. 389 
The specimens from Madagascar agree exactly with a typical 
example of this species purchased by the British Museum of Dr. 
Krauss. The figure in the ‘ Conchylien-Cabinet’ appears to be 
far more characteristic than that in Krauss’s work. 
PisiDIUM JOHNSON], sp. nov. (Plate XXII. figs. 28, 29.) BH» 
Shell minute, ventricose, inequilateral, glossy, finely concentrically 
striated, pale grey. Umbones large, inflated, without a small pointed 
nucleus. Posterior side longer and narrower than the anterior, 
obliquely sloping from the beaks, rounded at the extremity ; anterior 
end broader, blunter. 
Length 2 millim., width 24, diam. 1}. 
Hab. About 20 miles from Antananarivo (Johnson). 
This species is considerably like P. ventricosum of Prime, but is not 
not quite so swollen or so inequilateral. The beaks take the form of 
an apical glossy cap without any small pointed apex. The ligament 
is small and linear. 
EXPLANATION OF THE PLATES. 
PuateE XXT. 
Cyclostoma congener, p. 377. 
betsileoense, p. 376. 
, var., p. 377. 
johnsoni, p. 378. 
. Vitrina madagascariensis, p. 379. 
. Helix (Nanina) cleamesi, p. 379. 
(Macrocyclis?) covani, p. 381. 
13, 14. —— (Helicophanta) bicingulata, p. 380. 
Puate XXII. 
Figs. 1, 2, 3. Helix (Ampelita) shavi, p. 382. 
4, Bulimus (Rhachis) nigrilineatus, p. 382. 
5. Stenogyra (Clavator) johnsoni, p. 382. 
6. Melanatria johnsoni, p. 383. 
7. Ditto, lateral view of labrum. 
8,9. Ampullaria madagascariensis, p, 384. 
10, 11. Cleopatra trabonjiensis, p. 384. 
12, 13. Limnea electa, p. 385. 
14, 15. Physa lamellata, p, 386. 
obtusispira, p. 386. 
18, 19. —— madagascariensis, p. 386. 
20, 21, 22. Planorbis madagascariensis, p. 387. 
23, 24. Neritina fulgetrum, p. 387. 
25, 26, 27. Corbicula madagascariensis, p. 388. 
28, 29. Pisidiwm johnsoni, p. 389. 
X 
