OCR Text |
Show 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 JOHNSONI, sp. nov. (Plate XXII. figs. 28, 29.) 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 2-i-, diam. 1J. 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. PLATE XXI. Fig. 1. Cyclostoma congener, p. 377. 2. betsileoense, p. 376. 3. , var., p. 377. 4, 5. johnsoni, p. 378. 6, 7. Vitrina madagascariensis, p. 379. 8, 9. Helix (Nanina) cleamesi, p. 379. 10, 11, 12. (Macrocyclis ?) covani, p. 381. 13, 14. (Helicophanta) bicingulata, p. 380. PLATE XXII. Figs. 1, 2, 3. Helix (Ampelita) shavi, p. 382. 4. Bulimus (Bhachis) 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. Limncea electa, p. 385. 14, 15. Physa lamellata, p. 386. 16, 17. 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. Pisidium johnsoni, p. 389. |