ORTMANN : TERTIARY INVERTEBRATES. l6l 



GASTROPODA. 

 Fam. PATELLIDsE Carp. 



Gen. PATELLA L. 

 90. PATELLA PYGM/EA Ortmann. 



PI. XXX, Fig. r~ c - 

 1899 P. p. Ortmann, in: Amer. Journ. Sci., v. 8, p. 430. 



Shell subconical, outline regularly oval. Apex situated in the anterior 

 half. Surface with fine, crowded, a little unequal, radial ribs, crossed by 

 concentric lines of growth, and very finely granulated. 

 Length, 7 mm ; width, 5 mm ; height, 4 mm. 



Remarks: This may be an Acmcea. Pilsbry (1891, p. 7) says of 

 Acmcea: the shells may generally be distinguished from Patella by the 

 different texture and the marginal border of the inside. The presence or 

 lack of this border cannot be ascertained in our specimens, since the in- 

 terior is filled with matrix. 



There already exists an Acmcea heroldi forma Pygmcea Dunker (see : 

 Pilsbry, 1891, p. 45). If our species should prove to belong to Acimca, 

 the specific name is ill chosen, but cannot be changed, unless pygnicca 

 Dunker is regarded as a good species. 



Record of specimens: Punta Arenas, horizon III (upper Magellanian) ; 

 i sp. 



Fam. FISSURELLIDA1 Riss. 



Gen. FISSURELLA Brug. 

 91. FISSURELLA EURYTRETA Cossmann. 



PI. XXX, Fig. 8. 



1899 F. e. Cossmann, in : Journ. Conchyliol., p. 3 (of sep. cop.), pi. 1 1, f. i. 



Shell depressed, elongated-elliptical ; foramen subcentral, large, ellip- 

 tical. Surface with radiating ribs. 



Length, 21 mm; width, 12 mm; altitude, 5.5 mm. 



Remarks : Surface ornaments not seen in our individual, which is a cast. 



Record of specimens : Upper Rio Chalia ; i cast. 



Distribution: Jegua quemada, Suprapatagonian beds (Cossm.). 



