1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 393 
Variable in shape and degree of sculpture development, as noted by 
Smith. A shell from Elisabethville (Pl. XXXI, fig. 8) is rather wide 
(as in U. luapulaensis Preston), strongly sculptured, the corrugation 
becoming weaker toward the basal margin and more or less parallel to 
growth lines. | : 
In a Lukonzolwa shell (Pl. XXXII, fig. 9) the corrugation is finer, 
subobsolete in the lower third. 
Specimens from Kachiobwe (Pl. XX XI, fig. 10) and Kasenga have 
corrugation close to the beaks only, a few narrow folds appearing farther 
down on the posterior slope. There are many inconspicuous green rays, 
in the region of the beaks. In sculpture these examples are like U. 
luapulaensis Preston. 
Length, 27.5 mm.; height, 18.3 mm.; diameter, 12.0mm. Elisabethville 
Bee Aa Bs 2 13:7 Lukonzolwa 
33.5 cig! 3° 5 f 13.8 Kachiobwe | 
Parreysia acuminata (H. Adams) 
Plate XX XI, Figure 13 
Umo acuminatus H. Apams, 1866, Proc. Zool. Soc. London, p. 376. E. A. SMITH, 
1888, op. cit., p. 56; 1892, Ann. Mag. Nat. Hist., (6) X, p. 127, Pl. xu, fig. 12. E. v. 
Martens, 1897, ‘Deutsch Ost Afr., IV, Beschalte Weichth.,’ p. 227, Pl. vit, figs. 11 
and 12. J. Turmxe, 1911, ‘Wiss. Ergebn. D. Z. Afr. Exp. (1907-08),’ III, p. 212. 
Nodularia acuminata H. Adams. Stmpson, 1900, Proc. U.S. Nat. Mus., XXII, 
p. 826. 
Unio (Cafferia) acwminatus H. Adams. Simpson, 1914, ‘Descript. Cat. of 
Naiades,’ p. 579. 
This is probably the Unio caillaudi H. Adams, 1866, Proc. Zool. Soe. London, 
p. 376; E. A. Smith, 1888, op. cit., p. 56, recorded from Lake Albert. 
Lake Albert: originally described from that lake, without more definite locality 
(S. Baker Coll.); near Kassenje (Stuhlmann Coll.; Schubotz Coll.). 
Lake Albert: Butiaba (Mearns Coll.). 
The figure represents a specimen collected by Mearns at Butiaba, 
Lake Albert, No. 215196 U.S. N. M. It measures: 
Length, 35.0 mm.; height, 18.0 mm.; diameter, 13.0 mm. 
Other Species of Parreysia Recorded from the Belgian Congo 
Parreysia horei (EK. A. Smith) 
Unio horei E. A. Smrru, 1880, Ann. Mag. Nat. Hist., (5) VI, p. 429; 1881, Proce. 
Zool. Soc. London, p. 299, Pl. xxxiv, fig. 37. E. v. MarrTEns, 1897, ‘Deutsch Ost 
Afr., IV, Beschalte Weichth.,’ p. 235. 
Grandidieria horei E. A. Smith. Bourcuienat, 1885, Bull. Soc. Malacol. France, — 
li, ps : 
