‘ 
1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 439 
Mutelina carret Putzeys. GurMain, 1911, Bull. Mus. Hist. Nat. Paris, p. 226. 
DAUTZENBERG AND GERMAIN, 1914, Rev. Zool. Afric., IV, 1, p. 69. G. C. Spencz, 
1923, Journ. of Conchology, XVII, p. 23. 
Pseudospatha leopoldvillensis Simpson, 1900, Proc. U. 8. Nat. Mus., XXII, p. 
577 (error for carre?). 
Pseudospatha carret Putzeys. C.R. Barrasr, 1913, Ann. Soc. Malacol. Belgique, 
XLVII, (1912), p. 111. Simpson, 1914, ‘Descript. Cat. of Naiades,’ p. 204. 
Chelidonopsis roubaudi GERMAIN, 1908, Bull. Mus. Hist. Nat. Paris, p. 161, figs. 
31 (on p. 161) and 33 (on p. 162); 1909, Arch. Zool. Expér. Gén., XLI, pp. 4-34, 
figs. 1, 4, and 6 (anatomy). Simpson, 1914, ‘Descript. Cat. of Naiades,’ p. 1369. 
Stanley Pool near Leopoldville (type locality; collector not recorded) and near 
Brazzaville (type locality of rowbaudi; Roubaud Coll.). Lower Congo (P. Hesse 
Coll.). Lualaba River at Kibombo (J. Bequaert Coll.). . 
Also found in the French Congo at Ngandu on the right bank of the Congo River 
(F. M. Dyke Coll.)., and at Makoua (Fourneau Coll.). 
IrrtpiIna Lamarck 
Iridina LaMarcxk, 1819, ‘Hist. Nat. Anim. sans Vertébres,’ VI, 1, p. 88. Mono- 
typic for Iridina exotica Lamarck. 
_ Platiris I. Lea, 1838, Trans. American Phil. Soc., VI, pp. 118 and 144. On p. 
118, where the genus is first proposed, it contains only Iridina exotica Lamarck and 
Spatha nilotica (Sowerby). Type by present designation: Jridina exotica Lamarck. 
Platyiris Acassiz, 1846, ‘Nomenclator Zool., Index Univ.,’ p. 295. Emendation | 
of Platiris Lea. 
Eufira Gisten, 1848, ‘Naturgesch. Thierr. f. Héhere Schulen,’ p. 173. Sub- 
stitute for Iridina Lamarck. 
Mutelidz having a solid, oblong or oval shell with a strongly developed hinge- 
plate set with many short teeth (taxodont hinge). Muscle impressions as in As- 
patharia. 
Mantle margins united below the branchial orifice (for about 1 the mantle length 
in I. spekit). Outer gill nearly as large as the inner. 
Tridina resembles Mutela by the strong development of mantle con- 
crescence; there are also some partial transitions in the hinge structure, 
Von Martens and Simpson have, indeed, united these two groups. While 
this may be a logical course in view of what we now know of these ani- 
mals, we prefer for the present to segregate the strongly taxodont forms 
from the weakly taxodont or anodont genus Mutela, as Germain and 
some others have done. The soft anatomy has been investigated only 
in I. speki. 
The genus is restricted to Africa. 
Three subgenera appear distinguishable as follows: 
1. Teeth small and very numerous throughout the heavy hinge-plate which bears a 
low prominence under the beak of the left valve; shell elongate. 
Subgenus Iridina Lamarck. 
Teeth rather coarse, irregular, the hinge-plate narrowed under the beaks...... ys 
