NODULARIA f IOOI 
radial wrinkles; epidermis reddish-brown becoming burnt- 
blackish on the border; pseudocardinals compressed, two in 
each valve; laterals delicate, curved; muscle scars shallow ; 
nacre rich blue, iridescent behind. 
Length 29, height 14.5, diam. 9.5 mm. 
Borneo. 
Unio trompi Drourr and Cuarrr, Mem. Soc. Zool. Fr., V, 
1892, p. 153, pl. v1, figs. 8-Io. 
Nodularia trompi Stmpson, Syn., 1900, p. 816. 
Elongaria trompi Haas, Con. Cab., Unio, 1910, pl. xvi, fig. 6. 
Remarkable for the peculiar subnodulous and granulated 
sculpture, which, on the anterior end, becomes somewhat con- 
nected and zigzagged, and for the intense burnt-brown and 
blackish epidermis. ‘The nacre in the specimens before me is 
very rich sky blue, and iridescent behind. 
Group of Nedularia olivaria. 
Shell thin, inflated, blue-green or olive-green, smooth, shin- 
ing, with two or more faint ridges on the posterior slope ; beaks 
and disk almost or quite destitute of sculpture; teeth greatly 
compressed, lamellar. 
NODULARIA OLIVARIA (Lea). 
Shell very thin, subinflated, irregularly long elliptical, in- 
equilateral; beaks moderately full and high, apparently with- 
out sculpture, or with only faint indications of it; anterior end 
rounded ; base lightly curved, full behind the middle, obliquely 
subtruncated behind; posterior ridge showing indications of 
being double, the region in front of it very full, the ridge end- 
ing in a blunt point on or above the median line; surface ap- 
parently smooth but having very fine growth lines and often 
faint, microscopic, radial sculpture; epidermis delicate bluish- 
green, often with a milky tint, darker on the dorsal slope 
where there are faint rays; teeth compressed, elevated into 
sharp lamellz ; beak cavities rather deep; nacre bluish with a 
decided milky tint. 
Length 40, height 22, diam. 15 mm. 
India. 
