SPATHA 



I 34 1 



"In form resembling An. senegalensis, but much flatter and 

 with a more reticulated surface. An. senegalensis is also char- 

 acterized by a radiating posterior rib, which is wanting in the 

 present species." 



Spatha pFi;i]"]?kriana (Bernardi). 



Shell oblong, subrhomboid, apparently convex and subsolid, 

 inequilateral ; beaks somewhat elevated ; posterior ridge round- 

 ed, ending near the base in a blunt rounded point, with a 

 slight, radial ridge above it; surface smooth, with concentric 

 striae ; epidermis greenish-black ; muscle scars well marked ; 

 nacre blackish-green behind, lighter in front. 



Length y2, height 36 mm. 



Gaboon ; West Africa. 

 Margaritana pfeifferiana Bernardi, Jl. de Conch., IV, i860, 



p. 331, pi. XII, figs. I, 2. 

 Margaron (Margaritmia) pfeifferiana Lea, Syn., 1870, p. 68. 

 Spatha pfeifferiana Simpson, Syn., 1900, p. 900. 

 Spatha pfeifferi Germain, Arch. Zool. Exp. et Gen., (5), I, 



1909, p. 56. 



The description given by M. Bernardi is very brief, several 

 of the important characters being entirely omitted. I have 

 based the above description largely on the excellent figures. 

 The species is remarkable for its dark color within and with- 

 out, being a blackish-green throughout. 



Germain, (I. c), remarks that it is, "perhaps, only a variety 

 of S. tawai Rang. 



Spatha daiiomeyensis (Lea). 



Shell elongate, subrhomboid, rather thin or scarcely sub- 

 solid, convex, inequilateral ; beaks moderately elevated, with 

 delicate, oblique sculpture ; posterior ridge full, rounded, end- 

 ing near the base in a bluntly rounded point ; dorsal and basal 

 margins nearly parallel, curved so that the outline of the shell 

 is slightly arcuate; anterior end rounded, usually a little nar- 

 rower than the hinder end ; posterior end obliquely truncate ; 

 left valve often having a feeble tooth ; muscle scars well mark- 



