1927] Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo . 847° 
SPHZRIUM Scopoli 
Spherium Scopoui, 1777, ‘Introductio ad Historiam Naturalem,’ p. 397. Mono- 
type: Tellina cornea Linnzeus. 
Cyclas BrucuimmRE, 1792, ‘Encyclop. Méthod., Vers,’ II, Pls. cccrt and cccur 
(including species of Cyrena, Corbicula, and Musculiwm, as well as Cyclas cornea). 
Lamarck, 1799, Mém. Soc. Hist. Nat. Paris, p. 84, monotypic for Tellina cornea 
Linnzus. 
Cornea MEGERLE V. MUuHLFELD, 1811, Mag. Ges. Naturf. Fr. Berlin, V, p. 56. 
Monotype: Cornea communis Megerle v. Miihlfeld = Tellina cornea Linneus. 
Corneola CLESsIN, 1890, in Westerlund, ‘Fauna Paliarct. Binnenconchylien,’ 
VII, pp. 6 and 8. Type by present designation: Tellina cornea Linnzeus. Not 
Corneola Held, 1837). | 
Corneocyclas Firussac, 1818, ‘Dict. Sci. Nat.,’ XII, p. 278. Type by present 
designation: Cyclas cornea Draparnaud.! 
Spheriastrum Boureuienat, 1854, Rev. Mag. Zool., (2) VI, pp. 668, 669, and 
674. ‘Type by designation of Dall (1903, Proc. Biol. Soc. Washington, XVI, p. 7): 
Cyclas rivicola Leach = Cyclas cornea Draparnaud. , 
Cyrenastrum BouRGUIGNAT, 1854, Rev. Mag. Zool., (2) VI, pp. 668, 669 and 674. 
Monotype: Spherium solidum Normand. 
Cornecyclas P. Hesse, 1916, Nachrichtsbl. Deutsch. Malakoz. Ges., XLVIII, 
p. 123. Misspelling of Corneocyclas. : 
Shell oval, squarish or bluntly triangular, usually rather solid and concentrically 
striate, with nearly median, rounded beaks without projecting caps. 
Siphons short and separate. 
The genus is mostly Holarctic in distribution and is not known from 
the Oriental and Australian Regions, but a few species occur in Africa 
to the Cape. | 
Germain has proposed a subgenus Serratispherium (1909, Arch. 
Zool. Expér. Gén., XLI, p. 114) for the African Sphertum courtete 
Germain, characterized by ‘“‘les lamelles de sa charniére fortement et 
réguliérement serrulées.”” Cf. Sphertwm solidum (Normand), type of 
Cyrenastrum Bourguignat. | 
The following African species have been described. Several of them, 
such as S. abyssinicum and S. nyanze, may belong to Musculium, but 
we have not seen them. 
Spherium abyssinicum PoLLoNERA, 1898, Boll. Mus. Zool. Anat. Comp. Torino, 
XIII, No. 313, p. 12, Pl., figs. 28 and 29. From the sources of the Addas River, near 
Adi Caie, Eritrea. : : 
Spherium boccardi PoLLONERA, 1898, Boll. Mus. Zool. Anat. Comp. Torino, 
_ XIII, No. 313, p. 12, PL., figs. 30 and 31. Senafe, in the Scimenzana River, Eritrea. 
Spherium capense (Krauss). See p. 349. 
1Dall (1903, Proc. Biol. Soc. Washington, XVI, p. 7) named Tellina pusilla Gmelin as the type of 
Corneocyclas, in which case that name would replace Pisidiwm C. Pfeiffer. But, as will be shown else- 
where, Tellina pusilla Gmelin was not originally included by Férussac in Corneocyclas and it cannot be 
shown to be positively identical with Cyclas fontinalis Draparnaud, one of the species mentioned by 
Férussac. Dall’s fixation of type is therefore invalid. 
