ORTMANN : TERTIARY INVERTEBRATES. 131 



Record of specimens: Mouth of Santa Cruz River, 2 double valves; 

 Paso del Rio Santa Cruz, i right valve; Upper Rio Chalia, 2 casts; 

 Punta Arenas, horizon V (Patagonian beds), 2 right valves. 



Distribution: Jegua quemada, Jack Harvey, La Cueva, Suprapatago- 

 nian beds; perhaps also from Santa Cruz, Patagonian beds (v. Ih.); 

 Santa Cruz (Phil.). Navidad beds of Chili: Navidad, Matanzas, Lebu 

 (Phil.). 



Affinities: Philippi compares this species with L. radula Lmck. = bore- 

 alis (L.) (see : Hoernes, 1870, p. 229, pi. 33, f. 4), to which it is very closely 

 allied indeed. L. borealis is Miocene to Recent in Europe, and also 

 Miocene to Recent in California (see: Gabb, 1869, p. 100). In L. pro- 

 inancana the lateral hinge teeth are more distinct than in the European 

 species ; I have seen, however, in the Princeton collections, individuals of 

 L. borealis from the Pliocene of Italy, which also have distinct lateral 

 teeth. L. pmecedens v. Koenen (1868, p. 246, pi. 28, f. 8) from the Mid- 

 dle and Upper Oligocene of Germany is hardly distinguishable from L. 

 borealis. 



56. LUCINA ORTMANNI v. Iliering. 



PI. XXVII, Fig. 5. 

 1899 L. o. v. Ihering, in: N. Jahrb. Miner., etc., v. 2, p. 18, pi. 2, f. 3. 



Shell suborbicular, convex; posterior dorsal margin straight, forming 

 an obtuse angle with the posterior margin. Anterior dorsal margin 

 straight, forming an obtuse angle with the anterior margin. No lunula. 

 Beak small. Anterior, ventral, and posterior margins forming part of a 

 circle. Two very blunt ridges running from the apex toward the middle 

 and lower part of the posterior margin (according to v. Ihering) : these 

 ridges are not shown in his figure. In our specimen an indistinct depres- 

 sion runs toward the lower posterior margin, which would correspond to 

 the space between the ridges mentioned by v. Ihering. Surface almost 

 smooth, very finely concentrically striated, and with concentric growth- 

 lines, but no elevated lines are present as in the two preceding species. 



Length, 22 mm; height, 20 mm; diameter, 6 ( x 2) mm. 



Record of specimens : Mouth of Santa Cruz River; i right valve. 



Distribution: Santa Cruz, Patagonian beds (v. Ih.). 



Affinities: v. Ihering compares this species with L. globosa Ad. We 

 know several Tertiary species, which resemble this one in form and sculp- 



