APPENDIX. 



377 



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. J-. 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. 1843, 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 lyrse (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 impression 

 large, lanceolate. ^.-.-5-. Philippines. 



Nucula delphixodonta (t. 20, f. 16), Mighels, Proc. Bost. 1 ; Bost. 

 J. 4, p. 40, t. 4,/. 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. 



Nucula tenuisulcata (t. 20, f. 17), Couth. Bost. J. 2, £>. 64, t. 3, 

 /. 8. — X. 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 lyrae 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, f...-^-- N. America. 



Nucula pygiyLea * (t. 20, f. 18), Munster. — Phil. Sic. 2, p. 46. — 

 Midd. Mai. lios. 3, p. 28. — N. lenticula, Mbller, p. 17. — Leda p. 

 Brit. Mol. 2, p. 230, t. 47,/. 10.— Yoldia p. Midd. Sib. t. 18,/. 15 

 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 ; snorter extremity rounded-angular ; um- 

 bones prominent, swollen ; beaks small, not inclined ; no dorsal im- 



2 H 



