NODUL ARIA 1003. 
NODULARIA PECTEN Preston. 
“Shell elongately ovate, rather thin, covered with a finely 
laminiferous periostracum of a pale bluish-green color shad- 
ing to yellowish-green towards the margins, finely concentrical- 
ly striate and posteriorly ribbed, especially on the left valve; 
umbones rather smal!, moderately prominent; dorsal margin 
very slightly arched; ventral margin gently curved; anterior 
side rounded; posterior side obtusely rostrate below, sloping” 
above; hinge-teeth in both valves weak, anteriorly erect in 
the right valve, sinuous and almost twisted in the left; poste- 
rior teeth nearly straight, moderately elongate ; adductor scars 
scarcely perceptible ; interior of shell pearly. 
Long. 10, lat. 33.5, diam. 12 mm.” (Preston). 
Type locality, Pitsanuloke, N. Siam. . 
Nodularia (Nodularia) pecten Preston, Rec. Ind. Mus., VII, 
1912, p. 292, pl. vitl, figs. 3, 4. 
“The author follows Simpson in placing this and the next 
two species (nuttalliana and involuta) in the Section Nodularia, 
theugh, owing to the very different texture of the shells, it 
is somewhat difficult to understand his reasons for so placing 
them.” 
NODULARIA NUTTALLILIANA (Lea}. 
Shell irregularly elliptical, scarcely subsolid, subinflated, in- 
equilateral; beaks high and rather full; anterior end rounded: 
base lightly curved, full behind the middle, then obliquely sub- 
truncated; dorsal slope obliquely subtruncate; posterior ridge 
high, subangular, ending on the median line in a point; epi- 
dermis yellowish-green with paler bands and faint rays on the 
dorsal slope, nearly smooth, shining, feebly rayed; pseudo- 
cardinals compressed, elevated; laterals curved, high; muscle 
scars well marked; beak cavities impressed; nacre whitish or 
yellowish, with a dark, bluish blotch in the beak cavities. 
Length 25, height 20, diam. 13.5 mm. 
India. 
