1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 269 
Melania loricata Reeve, 1860, ‘Conchol. Iconica,’ XII, Melania, Pl. xxx, fig. 
198 (without locality). iiss! | 
Melania matoni var. loricata Reeve. O. Barrarr, 1885, 24.u.25. Ber. Offen- 
bacher Ver. f. Naturk., p. 191. C. R. Barrer, 1913, Ann. Soc. Zool. Malacol. 
Belgique, XLVII, (1912), p. 100. 
Pirena granulosa LAMARCK, 1822, ‘ Hist. Nat. Ania: sans Vertébres,’ VI, 2, p. 170. 
DELESSERT, 1841, ‘Rec. Coq. Lamarck,’ Pl. xxx1, figs. la-b. 
Melania oeeellcle I. Lea, 1850, Proc. Zool. Shs. London, p. 192 (locality unknown). 
Brot, 1868, ‘Matér. Et. Mélaniens,’ IT, p. 45, Pl. 1, figs. 4 and 5 (Gaboon). 
Melania quadriseriata var. carinata Brot, 1868, ‘Matér. Et. Mélaniens,’ II, 
p. 47 (new name for M. mutans Gould). 
Banana (P. Hesse Coll.). Dredged at the mouth of the Congo between Point 
Padrado and Shark Point (Gruvel Coll.). 
This species is found along the West Coast of Africa from Senegal to Angola. 
Landana at the mouth of the Shiloango River (Portuguese colony 
of Cabinda) (J. Bequaert Coll.). San Antonio, on the southern shore 
of the Congo estuary, in Angola (H. Lang Coll.). Malela; Kunga; 
Banana; Moanda (H. Lang Coll.). 
Although the remarkable polymorphism of this species has long 
been recognized, the series of thousands of specimens collected by the 
Congo Expedition gives occasion for further statement and illustration. 
The embryonic stage and the beginning of the neanic are unknown. 
The sculpture in the earliest stages seen, and as far as a mid-neanic 
stage, consists of numerous axial ribs crossed by four low spiral cords 
which are strengthened on the ridges. Just above the suture a smooth 
cord revolves, or it may be covered. The base has many spiral cords, not 
tubercular. After this stage, the species may assume either of three 
forms, which we designate I, II, III. 
L. In the form poe G po Taare the sculpture just described 
continues to the adult stage, the ribs becoming somewhat curved or 
protractive in the last three or four whorls. In aged individuals they 
become irregular, and the spiral cords lose their tubercles to a great 
extent (Pl. XXIV, figs. 3-3f, and others). 
This strain was doubtless the original form of the species. 
Two forms of granulosa are distinguishable: the typical granulosa 
in which the axial ribs are strong (Pl. XXIV, figs. 3, 3e¢) anda form in 
which they are much smaller and more numerous (Pl. XXIV, fig. 6). 
II. In the form fusca the length of the granose-costate stage varies 
individually. A keeled stage begins by gradual enlargement of the upper 
spiral cord and of the fifth or smooth one, in the suture; at the same time 
the second to fourth cords rapidly fade out. The three enlarged spirals 
I IS 
1Melania loricata Reeve appears to be an exact synonym. 
