APPENDIX. Sitek 
white epidermis, quite smooth, gaping at both ends; slopes of the 
dorsal edge slight, scarcely curved : no dorsal impressions; ventral 
edge arcuated, rising at both ends; umbones small, yet prominent ; 
inside pearly white; teeth numerous, about equal on either side of 
the hinge. 3. Singapore. The original description, like all of 
Hinds’s, is too brief; the above has been drawn up from one of the 
types. 
NucuLa RETICULATA (t. 19, f. 48), Hinds, Z. P. 1848, p. 100. 
Small, oval, subequilateral, acuminated and subrostrated medially at 
one end, attenuated and rounded at the other, subventricose, white, 
deeply and closely sulcated throughout, the lyre (or raised lines) not 
exactly concentric, though running from side to side, their intervals 
crossed by very minute radiating “lines : ventral margin arcuated ; 
beaks moderately prominent, scarcely inclined ; chief dorsal i impression 
large, lanceolate. 4...4. Philippines. 
NucuLa DELPHINODONTA (t. 20, f. 16), Mighels, Proc. Bost. 1; Bost. 
J.4, p. 40, t.4, f.5. Minute, ovate, rather oblique, extremely inequi- 
lateral, not thin, ventricose, glossy, yellowish olive, not rayed, nearly 
smooth ; ventral edge arcuated; anterior extremity rounded, the 
front edge arched ; posterior termination abrupt, yet the hinder edge 
subarcuated: umbones rather swollen, yet not prominent; teeth very 
long, slender, pointed, 3 on one side, 7 on the other; no dorsal im- 
pressions. Maine, N. America. 
NvcuLa TENUISULCATA (t. 20, f. 17), Couth. Bost. J. 2, p. 64, t. 3, 
Ff. 8.—N. minuta, Gould, p. 101.—Dekay, 181. Oblong-lanceolate, 
very inequilateral, rounded on one side, greatly produced attenuated 
and rostrated on the other; tolerably strong, slightly compressed, 
ashy greenish yellow, closely sulcated concentrically, the lyre and 
their simple intervals of equal size; ventral edge much arcuated ; 
longer dorsal edge subretuse ; shorter dorsal edge arcuated; from the 
scarcely prominent beaks to the narrow truncated tip of the rostrum 
run two indistinct ridges or angles, the space between which is flat- 
tened, and the area above them lanceolate and impressed, but the 
dorsal lips pouting; inside white; teeth from 12 to 14 on one side, 
from 16 to 18 on the other. 2...,%3. N. America. 
NucuLa PYeM&a * (t. 20, iS 18), “Munster.—Phil. Sic. 2 2, p. 46.— 
Midd. Mal. Ros. 3, p. 28. se Np LENTICULA, Moller, p. 17.—LmEDA P. 
Brit. Mol. 2, p. 230, t. 47, f. 10.—Yorpra P. Midd. Sit. 18; fs 
to 18. Minute, triangular-oval, subequilateral, ventricose, smooth ; 
the polished cuticle yellowish olive; ventral edge entire, arcuated, 
rising at both ends; extremity of the longer side briefly subrostrated, 
its tip bluntly acuminated ; shorter extremity rounded-angular; um- 
bones prominent, swollen; beaks small, not inclined; no dorsal im- 
2H 
