NODULARIA 1023 
Unio gerrardi von Martens, Besch. Ost. Af., 1897, p. 223, pl. 
VIt, fig. 5. 
Nodularia nilotica var. gerrardi Simpson, Syn., 1900, p. 822. 
Possibly distinct from N. nilotica. The beaks appear to be 
fuller, higher and more elongated than those of nilotica, and 
von Martens states that they have V-shaped sculpture instead 
of scattered pustules, but there is much variation in this char- 
acter even in different specimens of the same species in this 
group. The shell is probably more inflated than that of N. 
nilotica. 
NODULARIA BAGDADENSIS (Bourguignat). 
Shell somewhat elongated, irregularly elliptical, rather thin, 
convex or but slightly inflated, inequilateral; beaks but little 
elevated; dorsal outline lightly curved; anterior end rounded; 
base line curved, fuller behind the middle; posterior ridge low, 
inclined to be double, ending in a blunt point or a feeble bian- 
gulation about on the median line; dorsal slope obliquely trun- 
cate; surface with delicate, concentric sculpture; epidermis 
brownish-green ; teeth lamellar and delicate. 
Length 56, height 33, diam. 19 mm. 
Environs of Bagdad? 
Unio bagdadensis Bourcurcnat, Test. Nov. Saulc., 1852, p. 
30; Cat. Rais., 1853, p. 78, pl. Iv, figs. 4-6—KosBeEvt, Icon. 
new ed., XVIII, 1912, p. 64, fig. 2685. 
Margaron (Unio) bagdadensis Lea, Syn., 1870, p. 46. 
Nodularia bagdadensis Stmpson, Syn., 1900, p. 822. 
More delicate and compressed than N. nilotica and having 
decidedly lamellar pseudocardinals. 
This appears from the figures and descriptions to be a mem- 
ber of the egyptiaca group of Nodularia. It is possible that 
it came from Asia Minor, but more likely that it is an African 
species. The Unio eucyphus of Bourguignat, which he credits 
to this region, is believed by Lea to be the U. egyptiacus of 
Cailliaud, and I agree with him. This may be merely a pecu- 
liar form of the same thing. 
