1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 431 
Tridina celestis I. Lea, 1838, Trans. American Phil. Soc., N.S., VI, p. 82, Pl. 
xxi, fig. 70 (Africa) (1836, ‘Synopsis of Naiades,’ p. 57, without description). 
Mutela rostrata Rang. Jicxrxi, 1874, Nova Acta Ac. Nat. Cur. Dresden, 
XXXVITI, 1, p. 269. Simpson, 1900, Proc. U. 8. Nat. Mus., AAMT, p- 905; 1914, 
‘Descript. Cat. of Naiades,’ p. 1359. 
Mutelina rostrata Rang. GERMAIN, 1908, in A. Chevalier, ‘1’ Afrique Centrale 
Frangaise,’ p. 567; 1913, Bull. Mus. Hist. Nat. Paris, p. 294. C. R. Barresr, 1913, 
Ann. Soc. Zool. Malacol. Belgique, XLVII, (1912), p. 112. 
Mutelina legumen A. 'T. DE RocHEBRUNE, 1886, Bull. Soc. Malacol. France, III, 
p. 6, No. 2. 
Mutelina prasina A. 'T. DE ROCHEBRUNE, 1886, op. cit., III, p. 7. 
Mutelina thollont A. T. DE RocHEBRUNE, 1886, op. cit., III, p. 6, No. 3. 
Mutelina thottont Simpson, 1900, Proc. U.S. Nat. Mus., XXII, p. 906. 
Zongo on the Lower Ubangi (Poutrin Coll.); Kasai (Wissmann Coll.); Gancini 
or Nganchu on the right bank of the Congo (type locality of M. legumen, M. prasina, 
and M. tholloni; Thollon Coll.). 
Stanleyville, numerous specimens (Lang and J. Bequaert Coll.). 
Channel leading from Lake Kabamba to the Lualaba River at 
Mulongo (J. Bequaert Coll.). 
This widely spread species is abundant in Stanleyville. The color is 
usually in great part black to brownish-olive shading into blackish green 
or dark green toward the beaks, and generally with many narrow dusky 
rays, rather weak or indistinct; a few examples are brownish-olive with 
indistinct zones of citrine-drab. The interior in young shells is alice 
blue with red reflections, but in the old ones it becomes mainly livid 
pink. The contour varies as shown in the figures. The post-dorsal 
wing is always very narrow and roughened by fine, crowded, cuticular 
lamins. The beaks, always eroded, are very low and a trifle behind the 
anterior fourth of the length. There is a very small anterior-dorsal 
wing, rounded at the end. The posterior end is bluntly pointed, above 
it obliquely truncate, and the basal margin rises enough to bring the 
point about midway of the height. | 
Length, 99.0 mm.; height, 33.0 mm.; diameter, 19.5 mm. 
‘f 104.0 ey 400 | 20.5 
‘104.0 deers A rosea) 
Mutela garambe, new species 
Plate XL, Figures 1, la, 2 
Middle Garamba River, in sand and mud of the river bed, February, 
1913 (dry season; Lang and Chapin Coll.). 
The shell is rather solid, trapezoidal, the height contained 2%4 times in the length, 
with subparallel dorsal and ventral margins. Upper margin straight; basal margin 
nearly straight; the anterior end is broadly rounded, posterior end obliquely truncate, 
