1927] Pilsbry-Bequaért, The Aquatic Mollusks of the Belgian Congo 403 
Length, 45.0 mm.; height, 25.0 mm.; diameter, 17.5 mm. Type. 
ee BT ae A) is 14.0 Paratype. 
is 43.0 ‘24.0 “ 17.5 Ks 
ere er NS e 22.00 ss 
This species appears to be closely related to Unto tricolor Kiister, 
from the Nile in Egypt, differing by the smaller size and corrugated 
posterior slope, which is not green as described and figured by Kiister. 
The least eroded example shows two series of V-shaped loops near the 
beaks, which will therefore doubtless prove to have typical Cexlatura 
sculpture. 
A shorter specimen taken by Lang at Medje, which we refer a 
visionally to this species, measures: length, 34.0 mm.; height, 21.0 mm.; 
diameter, 13.5 mm. 
Celatura'stanleyvillensis, new species 
Plate XX XII, Figures 3, 3a, 4; Plate XX XIII, Figure 3 
Congo River at Stanleyville (Lang and Chapin, and J. Bequaert 
Coll.). 
The shell is moderately solid, somewhat swollen, elliptical; the dorsal and ventral 
‘margins about equally curved; the anterior end rounded, posterior end obliquely 
truncate above, rounded below. Posterior ridge is well rounded, usually with two 
narrow, slightly raised or sunken rays. Surface finely striate, the strize with cuticular 
edges. Behind and in front of the eroded beaks there is typically some oblique cor- 
rugation near the hinge line (but weak or wanting in many more or less eroded shells). 
‘The surface is dull, brownish olive to nearly black, or gray where the cuticular lamin 
are well preserved. The interior is pale pink (or nearly white). Teeth much com- 
pressed, as described for C’. mesafricana. 
Length, 52.0 mm.; height, 31.0 mm.; diameter, 22.0 mm. ‘Type. 
eo pew ean ¥-) 6 “ 22.0 Paratype. 
‘+ &8.0 he ea " 19.0 Bf 
eo DBAs te a: ta 22.5 ‘e 
The plump form and dull, laminate epidermis distinguish this species, 
which was taken in abundance. In young shells, up to about 25 or 30 
mm. long, the epidermal laminz are but little or not at all developed. 
The surface is somewhat glossy, olive to deep olive-buff with many narrow 
darker rays. 
Celatura briarti (Dautzenberg) 
Unio briarti DAUTZENBERG, 1901, Ann. Soc. Malacol. Belgique, XXXVI, Mém., 
p. 6, Pl. 1, figs. 3 and 4. Gurmarn, 19138, Bull. Mus. Hist. Nat. Paris, p. 291, Pl. 
x1, figs. 67 and 68. DAUTZENBERG AND Germain, 1914, Rev. Zool. Afric., IV, 1, 
p. 68. 
