128 PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 



V. Ihering has sent to us one right and one left valve of this species 

 under the name of C. patagonica ; they are from Santa Cruz, and he called 

 this species apparently by that name (patagonica) in 1899. But the ex- 

 ternal shape of the true C. patagonica of Sowerby is entirely different, and 

 we cannot regard it as this species, unless we assume that Sowerby's figure 

 is all wrong. There is, however, hardly anything that could warrant this 

 assumption, although there are discrepancies between Sowerby's diagnosis 

 and his figure. 



Record of specimens: Mouth of Santa Cruz River, 2 double, 20 right, 

 29 left valves ; Las Salinas, 3 right, 4 left valves ; Mt. of Observation, 

 upper horizon, 2 double, 12 right, 2 left valves. 



Distribution: Santa Cruz (Phil., v. Ih.); Patagonian formation (v. Ih.). 

 Suprapatagonian beds of Jegua quemada and La Cueva (v. Ih.). 



53. CARDITA PATAGONICA Sowerby. 



PI. XXVI, Fig. 8 M . 



1846 C.pat. Sowerby, in : Darwin, Geol. Observ. S. Amer., p. 251, pi. 2, f. 17. 

 1897 C. pat. var. v. Ihering, in: Rev. Mus. Paul., v. 2, p. 245. 



1899 C. psetidopatagonica v. Ihering, in: N. Jahrb. Miner., etc., v. 2, p. 16. 



1900 C. pat. Ortmann, in: Amer. Journ. Sci., v. 10, p. 380. 



Shell ovate, subtriangular, hardly oblique, as high as long, or higher; 

 apex very slightly inclined. Surface with 23-25 radial ribs, which are 

 rounded, not angular, and slightly squamuloso-nodose near the apex, but 

 toward the ventral margin they are crossed only by lines of growth. 



Measurements: Length, 20, 19 mm; height, 20, 20 mm. 



Remarks: In the external form our specimens agree with Sowerby's 

 figure, especially the almost upright apex is very striking. Sowerby, in 

 the diagnosis, calls the ribs narrow, angular and squamoso-serrate, char- 

 acters which are not supported by the figure, where the ribs appear broad, 

 rounded, and slightly nodulose. In all essential respects the figure cor- 

 responds with our specimens, with only the exception that it is almost 

 double the size (length, 35 ; height, 37). Since a large form, agreeing 

 with this figure has never been found by other collectors at Santa Cruz, 

 it seems possible that Sowerby's figure was drawn on an enlarged scale. 



V. Ihering, in 1897, mentions this smaller form from the so called 

 Santacruzian (= Suprapatagonian) beds, and calls it in 1899 C. pseitdo- 



