ORTMANN : TERTIARY INVERTEBRATES. 
83 
Fam. LEDI D/E Ad. 
Gen. LEDA Schum. 
24. Leda oxyrhyncha (Philippi). 
PI. XXVI, Fig. 2"A 
1887 Nuciila ox. Philippi, Tert. Quart. Verstein. Chiles, p. 197, pi. 41, f. 21. 
1900 Leda ox. Ortmann, in: Amer. Journ. Sci., v. 10, p. 378. 
Shell elongate, anterior end shorter, rounded, posterior produced and 
acutely rostrate. Posterior dorsal margin slightly concave, ventral margin 
evenly arcuate. An angular ridge runs from the apex to the posterior 
end, and, below this ridge, there is a slight depression. Surface of shell 
with concentric ribs, between which fine radiating striae are present, which 
do not cross the ribs. The part of the shell between the posterior dorsal 
margin and the radial ridge running to the posterior end (escutcheon) has 
more numerous anci finer concentric ribs. Anterior hinge teeth ca. 12, 
posterior ca. 19. 
Length, 10 mm; height, 6 mm. 
Remarks : The individuals from Santa Cruz are a little shorter than the 
figure given by Philippi, and the apex is a little more anterior. Of the 
casts from Arroyo Gio only one is large (length, 12 mm; height, 6 mm), 
and here the form and situation of the apex agree with Philippi’s figure. 
An external cast from the same locality shows the characteristic sculpture 
of this species. 
The radial striae, between the concentric ribs, are distinct only near the 
ventral margin ; toward the apex they are indistinct or even wanting. 
The original discription of Philippi does not give the details of sculpture 
mentioned above, so that there remains some doubt as to the identity of 
our form with the Chilian ; I have made the identification chiefly on the 
ground of the agreement in the general appearance, and because none of 
the characters given by Philippi contradicts it. 
Record of specimens ; Mouth of Santa Cruz River, 2 right, 2 left valves ; 
Arroyo Gio, 6 casts. 
Distribution: Navidad beds of Chili ; Lota, Lebu, Navidad (Phil.). 
Affinities : An allied form is known from New Zealand (“juengere Ab- 
teilung” = Pareora or Miocene), and figured but not named by Zittel 
