142 
PATAGONIAN EXPEDITIONS : PALEONTOLOGY. 
apex is, in V. namdadis , distinctly more anterior, and the sculpture seems 
to be different. 
According to v. Ihering, this species is closely allied to the living species 
V. exalbida Ch. from S. America. 
Gen. MERETRIX Lam. 
68. Meretrix (?) pseudocrassa (Ortmaini). 
PL XXIX, Fig. m*. 
1899 Cytherm ps. Ortmann, in: Amer. Journ. Sci., v. 8, p. 429. 
Shell very thick and solid, very convex. Outline almost circular, pos- 
terior end rounded. Apex at two-sevenths of the length. Lunula and 
area indistinct, nymphae deeply immersed. Exterior surface concentrically 
striated, but the adhering matrix obscures the details of sculpture. Ven- 
tral margin of shell not crenulated. Hinge with two strongly developed 
teeth, and a smaller anterior one. Posterior tooth distinctly divided by 
a groove, the middle one also divided on upper side. 
Length, 62 mm; height, 60 mm; diameter, 25 (x 2) mm. 
Remarks: I am unable to decide whether this species belongs really to 
Meretrix or not. The division of the posterior hinge teeth is in favor of 
this view, but I cannot make out whether there was a fourth (lunular) 
tooth ; we have only the right valve, and that part of it, where we should 
look for the groove that receives this tooth, is broken out. Perhaps it 
would be better to leave this species with Verms. 
Record of specimens : Punta Arenas, horizon III (upper Magellanian); 
1 right valve. 
Affinities: I have compared this species with the Pliocene V. crassa 
Phil., and the Cretaceous V. alia Phil., both from Chili. 
69. Meretrix iheringi Cossmann. 
PI. XXVIII, Fig. 5"> 6 . 
1897 Cytherea splendida v. Ihering, in: Rev. Mus. Paul., v. 2, p. 255, pi. 
6, f. 42 (non C. splendida Merian). 
