io6 
PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 
to be correct, the name of O. rostrata of Hupe antedates O. ingens of 
Zittel, and should be used accordingly. 
0. transitoria of Hupe (Philippi, p. 213, pi. 49, f. 9), from Coquimbo, 
Caldera and Navidad (Pliocene and Miocene of Chili) may also belong 
here. It is very broad, but agrees in this character with many individuals 
from Patagonia. O. transitoria of Moericke (1896, p. 576, pi. 12, f. 1), 
however, seems to belong to O. patagonica (see below). 
Lately, several species of Ostrea have been described by Grzybowski 
( 1 899, PP- 629-63 1 ) from the lower Miocene and Pliocene of northern 
Peru (Payta and Tumbez), of which O. latiareata (Miocene) and O. oculata 
and lunaris possibly also belong here. At any rate, they are closely 
allied to O. ingens, but the material described and figured is too poor to 
form an opinion upon. 
I shall now proceed to give a record of our specimens, adding under 
each locality the necessary notes, which would serve to support the views 
set forth above. 
Record of specimens : 
1. Mouth of Santa Cruz River; 12 double, 7 lower valves. 
One of them is my type of O. hate hen. 2 more of the double valves 
agree completely : they are broad, with distant lamellar In 2 more the 
lamellae are more Growded near the lower margin; 1 other is a little 
elongated, with crowded lamellae in the posterior third of the shell, other- 
wise like O. hatcheri. 5 are very large, greatly elongated (one of them 
figured on pi. XV and XVI), with the beak and area more elongated; one 
of them with distinct lateral furrows as in O. ingens from New Zealand; 
the lamellae are much crowded in the posterior part of the shell. 1 
further specimen is of medium size and elongated; the lamellae are 
crowded, except near the beak ; the area is long. Of the single valves 5 
small or medium sized are the typical O. hatcheri; form circular or 
broadly oval. 2 others are larger and more elongated, one of them very 
large, is very elongate, with the lamellae crowded in the posterior half ; area 
long and broad, with distinct lateral furrows. The other is a little smaller 
than this one, ovate, the area triangular, the lamellae crowded posteriorly. 
In all specimens from this locality the radial ribs of the surface are only 
slightly or not at all developed. 
As will be noticed, the typical O. hatcheri is represented, among these 
1 9 individuals, by only 8. The rest are transitions to O. philippii, and a 
few may be called O. philippii. 
