94 PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 



V. Ihering compares this species with A. imbricata, which is, according 

 to Dall (1889, p. 40), a living species of the West Indies. 



In my opinion the most closely allied forms are: A. tetragona Poli (= 

 navicularis Desh.) from the English Crag (see Wood, 1856, p. 76, pi. 10, 

 f. i), 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. occidentalis Phil, and A. paratina Dall 

 (Philippi, 1851, p. 15, pi. 4, f. 4, and Dall, 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. pseudonavicularis 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. 



(= Pectunculus Lamck.) 

 31. GLYCIMERIS IBARI (Philippi). 



PI. XXVI, Fig. i"-*. 



1887 Pectunculus ib. Philippi, Tert. Quart. Verst. Chiles, p. 190, pi. 40, f. 3. 

 1887 Pectunculus magellaniciis Philippi, ibid., p. 190, pi. 41, f. i. 

 ? 1887 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 



