ORTMANN ! TERTIARY INVERTEBRATES. 
1 2 I 
43. Mytilus magellanicus Chemnitz. 
PI. XXIV, Fig. 3. 
1785 M. mag. Chemnitz, N. syst. Conch. Cab., v. 8, p. 162, pi. 83, f. 742, 
743 - 
1843 M. mag. d’Orbigny, Voy. Amer. mer., v. 5, p. 647. 
1858 M. mag. Reeve, Conch, icon., v. 10, pi. 6, f. 22. 
1873 M. mag. Hutton, Cat. Tert. Moll. Ech., N. Zealand, p. 25. 
1886 M. mag. Hutton, in: Trans. N. Zealand Inst., v. 18, p. 365. 
1900 M. mag. Ortmann, in: Amer. Journ. Sci., v. 10, p. 378. 
Shell elongated-triangular, apex subacute ; dorsal margin slightly con- 
vex, forming an obtuse and indistinct angle with the posterior margin ; 
ventral margin straight or slightly concave, forming a rounded angle with 
the posterior margin. Surface of shell sculptured by radiating, wrinkled, 
dichotomous ribs. 
Length, 50 mm; height, 23 mm. 
Remarks: I have compared our specimens with recent specimens of 
M. magellamcus collected by Mr. Hatcher at various localities on the 
Patagonian coast, and find that they agree completely. 
Record of specimens: San Julian, Oven Point; internal and external 
casts of about 10 specimens. 
Distribution: Living: coast of Patagonia and Straits of Magellan. 
Fossil: Philippi (1887, p. 249) mentions M. magellanicus from Lota, Chili, 
“probably quarternary,” but does not give it in the text, pp. 200-202. 
Hutton records it from the Miocene (Pareora), Pliocene (Wanganui) and 
Pleistocene beds of New Zealand. 
Gen. MODIOLA Lamck. 
44. Modiola ameghinoi v. Ihering. 
PI. XXV, Fig. 2. 
1897 M. am. v. Ihering, in: Rev. Mus. Paul., v. 2, p. 233, pi. 6, f. 43. 
Shell oblong, elongate, subtrapeziform, smooth. Cardinal part of dorsal 
margin very slightly convex, posterior part slightly concave ; these two 
parts meeting at an obtuse angle ; posterior part passing in a regular curve 
