i5 2 
PATAGONIAN EXPEDITIONS : PALEONTOLOGY. 
Length, n mm; height 7.5 mm; diameter (of right valve), 2.5 mm. 
Cast from San Julian: length, 13 mm; height, 8 mm; diameter (double), 
5 mm. 
Remarks: So far no Corbula has been known from Patagonia. In C. 
birostris Phil., from Lota, Chili (Navidad beds), the genus is very doubtful. 
. Record of specimens : Mouth of Santa Cruz River, 8 double, 6 right, 8 
left valves ; Las Salinas, 1 left valve ; Mt. of Observation, upper horizon, 
1 left valve; San Julian, Darwin Station, 2 double casts. 
Affinities: The most closely allied form, in my opinion, is C. subcequi- 
valvis Sandb. (see: Boettger, 1870, p. 41, pi. 9 (8b), f. 16), from the Oligo- 
cene of Germany and Switzerland. In C. hatcheri the posterior truncation 
is less distinct, the lower margin is more arcuate, and the ribs of the sur- 
face seem to be stronger (Boettger calls them “thin” in C. subccquivalvis) . 
There are also some Miocene species of Europe and North America, 
which might be compared with C. hatcheri , but they do not approach it 
so closely as C. subcequivalvis. 
Fam. SAXICA VI DAE Gr. 
Gen. PANOPEA Men. 
81. Panopea ibari Philippi. 
pi. xxix, Fig-. 5. 
1887 Panopcea ibari Philippi, Tert. & Quart. Verst. Chiles, p. 167, pi. 35, f. 4. 
1899 Glycimeris ib. Ortmann, in: Amer. Journ. Sci., v. 8, p. 429 (non Gly- 
cimeris ibari (Phil.), see above, p. 94). 
Shell elongate-oval, moderately convex, with concentric undulations. 
Apex at two-fifths of the length, prominent. Both ends rounded, poste- 
rior distinctly narrower than anterior. Ventral margin arcuate. 
Length, 84 mm; height, 45 mm; diameter, 15 mm; apex at 35 mm 
from anterior end. Rel. H. : L. = 1 : 1.8; in another individual : = 1 : 2.0. 
Record of specimens : Punta Arenas, lower horizon, II (lower Magella- 
nian), 1 double, 2 right, 2 left valves. 
Distribution: Magellanes and Skyring Water (Phil.). 
