ORTMANN : TERTIARY INVERTEBRATES. 1 25 



49. CRASSATELLITES LONGIOR (v. Ihering). 



PI. XXVII, Fig. 2. 



1897 Crassatella I. v. Ihering, in: Rev. Mus. Paul., v. 2, p. 247, pi. 5, f. 

 34, pi. 6, f. 37. 



Shell elongate-triangular, slightly convex, thick. Apex at about y$ of 

 the length. Anterior end rounded, posterior produced and narrowed. 

 Posterior dorsal margin oblique, forming a blunt angle with the pos- 

 terior margin. Ventral margin curved anteriorly, almost straight pos- 

 teriorly, forming a distinct acute angle with the posterior margin. An 

 indistinct angulation runs down from the apex to the posterior angle. 

 Surface marked with shallow concentric furrows. According to v. Iher- 

 ing, the ventral margin is crenulated. 



Length, 44 mm; height, 27 mm; diameter, 8 (X2). Attains, accord- 

 ing to v. Ihering, almost double that size. 



Record of specimens : Lake Pueyrredon, base of Tertiary ; i right valve. 



Distribution: Jegua quemada, Suprapatagonian beds (v. Ih.). 



Affinities : This species resembles C. melina Conr. (see Whitfield, 1894, 

 p. 60, pi. 8, f. 11-13) from the Miocene of New Jersey, but it is more 

 elongated and less convex, and the ventral margin is straight in the pos- 

 terior part. A more remote resemblance exists with C. ponderosa Phil, 

 from the Navidad beds of Chili, the latter being larger, thicker, and less 

 elongate, with the ventral margin arcuate throughout. 



Fam. CARDITID^. Gill. 



Gen. CARDITA Brug. 

 50. CARDITA ELEGANTOIDES Ortmann. 



PI. XXVI, Fig. 5- c . 



1899 C. el. Ortmann, in: Amer. Journ. Sci., v. 8, p. 428. 



Shell subcircular, slightly oblique, with 18-19 radial ribs, which are 

 convex and obtuse, about as broad as the intervening furrows, and nodu- 

 lose. Lunula small, oblong. 



