ORTMANN I TERTIARY INVERTEBRATES. 151 



There are some species in the Eocene beds of France, which resemble 

 this one in outline, although they differ in other respects: M. levesqnci 

 Desh., M. lamberti Desh., and M. contortiila Desh. (Deshayes, 1860, p. 

 289, ff. pi. 1 8). 



Another closely allied form is M. trinacria Semp. (Speycr, 1866, p. 34, 

 pi. 3, f. 4) from the Oligocene of northern Germany, but it is smaller and 

 a little higher. 







Gen. LUTRARIA Lam. 

 79. LUTRARIA (?) UNDATOIDES Ortmann. 



PI. XXX, Fig. 3. 



1899 L. u. Ortmann, in: Amer. Journ. Sci., v. 8, p. 429. 



Shell almost elliptic, 1 1 / 2 times as long as high. Surface with strong, 

 and somewhat irregular, undulated concentric folds. Dorsal margin 

 almost straight, ventral margin slightly arcuate. Apex at y$ of the 

 length, prominent, rather sharp, incurved. Anterior and posterior ends 

 evenly rounded, and of the same height. 



Length, 32 mm ; height, 2 1 mm ; apex at 1 1 mm from anterior end. 



Remarks: Only the remote resemblance to L. tmdata Phil. (1887, p. 164, 

 pi. 33, f. 8-1 1 ) induces me to place this species with the genus Lntrarin. 



Record of specimens : Punta Arenas, horizon II (lower Magellanian), i 

 double valve (cast). 



Fam. CORBULID^E Flem. 



Gen. CORBULA Lam. 

 80. CORBULA HATCHERI Ortmann. 



PI. XXX, Fig. 4"-'. 



1900 C. h. Ortmann, in: Amer. Journ. Sci., v. 10, p. 371. 



Shell small, solid and thick, subovato-triangular. Right valve very 

 little larger than left, both moderately convex. Anterior end rounded, 

 posterior produced, subtruncate, an angular ridge running down from the 

 apex to the posterior angle. Ventral margin arcuate, posteriorly a little 

 concave. Lower margin of right valve reflected toward the left valve. 

 Surface with concentric ribs, which are rounded and rather crowded. 



