94 
PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 
V. Ihering compares this species with A. imbricata, which is, according 
to Dali (1889, p. 40), a living species of the West Indies. 
In my opinion the most closely allied forms are : A. tetMgona Poli (= 
navicularis Desh.) from the English Crag (see Wood, 1856, p. 76, pi. 10, 
f. 1), and said to be also Miocene and Recent. And further, a closely 
allied species is A. noce L. (Miocene to Recent, see Hoernes, 1870, p. 324, 
pi. 62, f. 4). 
Specimens of the same size of A. tetragona from the Pliocene of Mt. 
Mario, Rome, differ only in the more anterior position of the apex, finer 
ribs, and sharper carina. 
Although the type of A . noce is represented also in Eocene deposits by 
different species, none of these approach our species so closely as the two 
forms named [A. tetragona and noce), so that we have here a distinctly 
Neogene relation. 
Similar forms, for instance A. occidentals Phil, and A. paratina Dali 
(Philippi, 1851, p. 15, pi. 4, f. 4, and Dali, 1898, p. 621, pi. 33, f. 14), 
closely allied to the European A . noce , are found in Oligocene, Miocene, 
Pliocene, and Recent beds in Florida and the West Indies. 
Also A . psendonavicnlaris Tate (1886, p. 139, pi. 1 1, f. 8) from so-called 
“Eocene” beds of South Australia and Tasmania belongs into this group. 
Gen. GLYCIMERIS Da Costa. 
(= Pectunctdus Lamck.) 
31. Glycimeris ibari (Philippi). 
PI. XXVI, Fig. 
1887 Pectunculus ib. Philippi, Tert. Quart. Verst. Chiles, p. 190, pi. 40, f. 3. 
1887 Pectunculus magellanicus Philippi, ibid., p. 190, pi. 41, f. 1. 
?'i887 P. araucanus Philippi, ibid., p. 191, pi. 36, f. 2. 
.1897 P* pulvinatus cuevensis v. Ihering, in: Rev. Mus. Paul., v. 2, p. 238, 
pi. 7, f. 46, pi. 8, f. 50. 
1899 P. pulv. cuev. v. Ihering, in: N. Jahrb. Min. Geol. Pal., v. 2, p. 14. 
1900 P. ibari Ortmann, in: Amer. Journ. Sci., v. 10, p. 379. 
Shell large and thick, suborbicular or more or less oblique. Surface 
with radial striae, the striae are fine, but sharp furrows, separated by rather 
