PANAMIC-PACIFIC PELECYPODA 99 



Area Soiverbyi d'Orbigny, 1846, Voy. Ara^r. Merid., vol. 5, pt. 3. Mollusques, p. 637. 

 (Name changed because of A. biangulata Lamarck, not A. Soiuerbyi Sowerby, 

 1840.) 



Area (Scaphareaf) biangulata (Sowerby), Maury, 1922, Paleont. Amer., vol. 1 No. 

 4, pp. 191, 192. 



Area (Anadara) biangulata Sowerby, Hertlein and Strong, 1843, Zoologica, vol. 28, 

 pt. 3, No. 19, pp. 155, 156, pi. 1, fig. 3. 



Anadara (Seapharea) biangulata (Sowerby), Rost, 1955, Allan Hancock Pacific Expedi- 

 tions, vol. 20, No. 2, p. 201, text figs. 86, 87 a-c. 



Area gordita Lowe, 1935, Trans. San Diego Soc. Nat. Hist., vol. 8, No. 6, p. 16, pi. 1, 

 fig. 1. 



The shell is short, oblong, ventrlcose with full, wide umbos, the maxi- 

 mum inflation of the valves placed in the anterior-middle half of the shell, 

 the posterior side narrowed and subacuminate. Cardinal area of medium 

 height, wholly covered by the ligament on the posterior side and partly 

 so on the anterior side. Ribs, about 30 in number, are relatively narrow 

 and of the same width as their interspaces. The ribs are smooth or finely 

 beaded and connected by strong cross threads in the interspaces. 



Sowerby 's biangulata was not figured by its author and the types were 

 not located at the British Museum. The species was described from a single 

 specimen dredged by Cuming at Atacames, Ecuador. Several dead valves 

 were dredged off Esmeraldas by Olsson and Dranga in 1955. A small, left 

 valve was dredged by Dr. G. Petersen off Zorritos in northern Peru. 

 D'Orbigny's specimen of biangulata (name changed to Sowerbyi) was ob- 

 tained by M. Fontaine in the Guayaquil area. This specimen is presented 

 in the D'Orbigny Collection at the British Museum. It is a large, double- 

 valved shell and measures 67.5 mm. in length. 



Range — Lower California to northern Peru and the Galapagos Islands. 

 Mexico: Gulf of California. Ecuador: Esmeraldas; Atacames (Cuming). 

 Peru: Off Zorritos and in the Gulf of Guayaquil. Galapagos: Galapagos 

 (Hertlein and Strong). 



Subgenus ESMERAKCA new subgenus 



Type species, Anadara reinharti (Lowe). 



Shell with slightly unequal, convex valves and somewhat discrepant 

 sculpture. Cardinal area is high, trigonal, flat or nearly so, largely covered 

 by the ligament except for a narrow space along the anterior side, and 

 cut into by two or more tentlike incisions. Periostracum thin, with a row 

 of bristles along the ribbed interspaces. 



The type species Anadara reinharti has been refern;d by most authors 

 to Seapharea although often with much uncertainty. Rost noted a resem- 

 blance to species of Cunearea and to Larkinia. The approach of Esmerarea 

 to Cunearea is quite marked, especially by its somewhat unequal valves 

 and slightly discrepant sculpture, the greatest difference is in the characters 

 of the cardinal and ligamental areas. In Cunearea, the cardinal area is 

 usually quite high and trigonal, smooth and the ligamental coverage is 

 complete as well as lacking the tentlike incisions. 



