MIOCENE MOLLUSCA AND CRUSTACEA. 81 
Genus SYNDOSMYA Reclus. 
SYNDOSMYA? NUCULOIDES. 
Plate xv, figs. 7-9. 
Amphidesma nuculoides Conrad: Am. Jour. Sci., lst. ser., vol. 41, p. 347; Miocene Foss., 
DD. ¢o, El xi fie. (6: 
Abra nuculoides Con.: Acad. Nat. Sei. Phila., 1862, p.574; Meek, Cheek List, p. 11. 
“Ovate, convex, very inequilateral, with very regular minute concen- 
tric lines, posterior side subcuneiform; extremity acutely rounded; lateral 
teeth obsolete.” (Conrad.) 
The specimen which I have referred to this species is about one-half 
larger than Mr. Conrad’s figure, but in other respects closely resembles it in 
outline and general features. The shell is rather elongate-ovate, and mod- 
erately convex, and extremely thin and delicate in texture. The beak is 
small, situated rather within the anterior third of the length, behind 
which the shell is narrowed, the posterior end being more narrowly rounded 
than the anterior; basal and cardinal margins subparallel; surface with very 
fine concentric lines only, and with a very faintly defined, oblique, mesial 
sulcus. Internally there is a single, moderately strong, direct tooth beneath 
the beak, with a deep, wide pit in front, in the right valve, and a slight pro- 
jecting lamellar tooth near its extremity. No appearance of a posterior 
lateral tooth can be seen. Muscular imprints very faint, and pallial sinus 
shallow and obscure. It is not an Abra, as there are no lateral teeth. 
Locality: Shiloh, N. J. From the collection of the National Museum; 
but only a single right valve observed. 
MON XxIy——6 
