8o 
PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 
excavated in the middle. Ventral (larger) valve more convex than the 
dorsal, obtusely carinated. 
Measurements : (according to v. Ihering) Length, 19 mm. 
Width, 15 mm. 
Remarks: All our individuals are smaller than v. Ihering’s and less 
elongated, which is apparently due to the younger age : the lines of growth 
in v. Ihering’s figure indicate that the younger shell was comparatively 
broader. 
Record of specimens: Lake Pueyrredon, base of Tertiary, 12 sp. 
Distribution: v. Ihering does not give a locality, but simply states that 
this species comes from the Patagonian formation. Two individuals, sent 
by him to the Princeton Museum, are labelled : Santa Cruz. 
Affinities: the genus Bouchardia is represented so far only in the recent 
seas, and the typical species, B. tulipa (Blv.) is found on the coast of Brazil. 
MOLLUSCA. 
Pelecyfoda. 
Fam. NU C U LI DAE Ad. 
Gen. NUCULA Lamck. 
22. Nucula patagonica Philippi. 
Plate XXV, Fig. J a K 
1887 N pat. Philippi, Tert. &: Quart. Verstein. Chiles, p. 198, pi. 41, f. 8. 
1897 N. tricesima v. Ihering, in: Rev. Mus. Paul., v. 2, p. 243, pi. 4, f. 
21, pi. 5, f. 27. 
1899 N. pat. v. Ihering, in: N. Jahrb. Min. Geol. Pal., p. 15. 
1900 N. pat. Ortmann, in: Amer. Journ. Sci., v. 10, p. 379. 
Shell thick, very convex, almost triangular, oblique, apex forming almost 
a right angle. Posterior dorsal margin slightly convex, forming with the 
lower margin a strongly curved posterior angle. Anterior dorsal margin 
slightly concave, anterior end a little produced, and sharply curved. Sur- 
face smooth, with concentric lines of growth. Hinge teeth in two rows 
meeting at a right or slightly obtuse angle, anterior row consisting of ca. 
8, posterior of ca. 11-13 teeth. No crenulations on inner side of ventral 
margin. 
