PANAMIC-PACIFIC PELECYPODA 255 



lamina extending from the beak to the ventral margin. The anterior side is 

 strongly convex, its surface smooth or reticulated with small radial and con- 

 centric lines or riblets. The hinge formation is weak; the right valve has 

 two, small, pointed cardinal teeth, the left valve one; there are no lateral 

 teeth. External color white, pink or a rose-red. 



There are two species in the Panamic-Pacific region. As fossil, Lopho- 

 cardium is represented in the Caribbean Miocene with species known from 

 Costa Rica, Colombia, and the Dominican Republic. 



Lophocardinm cnmingii (Broderip) Plate 39, figures 1, la 



Cardium cumingii Broderip, 1833, Proc. Zool. Soc. London, p. 82. — Sowerby, 1840, Conch. 



Illust. Cardium, p. 1, No. 11, fig. 5. — ^Reeve, 1844, Conch. Icon., vol. 2, Cardium, 



pi. 12, fig. 59. 

 Cardium (Laevicardium) cumingii Sowerby, Strong, Hanna and Hertlein, 1933, Proc. 



California Acad. Sci., ser. 4, vol. 21, p. 118 Acapulco. 

 Protocardium {Lophocardium) cumingii Sowerby, Maxwell Smith, 1944, Panamic Marine 



Shells, p. 58, fig. 738. 

 Cardium {Lophocardium) cumingii Broderip, Hertlein and Strong, 1955, Bull. Anner. 



Mus. Nat. Hist., vol. 107, art. 2, pp. 185, 186, pi. 2, figs. 3, 4, 7, 8. 



The shell is thin and fragile, broadly subovate and strongly convex or 

 inflated across the anterior-middle zone with high, full umbones ending in 

 small beaks inrolled against the hinge. The posterior side is shorter, strongly 

 contracted and with an open gap at the end. The anterior and middle sur- 

 face of the shell appears smoothish but on closer inspection, it is seen to 

 be covered with numerous, close-set, radial riblets, uniformly spaced be- 

 tween wider interspaces and weakly reticulated by irregular, threadlike 

 concentrics; the posterior surface is sculptured only with crowded growth 

 threads. The posterior-umbonal lamina is formed of elongated, hollow cells 

 of periostracum which stands erect in the living shell but when dead gen- 

 erally lies flattened appressed against its surface. The cardinal teeth are 

 small but fully formed; there are no lateral teeth but a small lamina lies 

 under the posterior margin of the right valve forming a groove which serves 

 as a sort of a socket for the lodgement of the margin of the opposite valve. 

 The color of the shell is usually pink or coral-red in various shades, the thin 

 periostracum generally inconspicuous, but where massed together as on 

 the posterior end, it is light straw-colored. A specimen measures as fol- 

 lows: Length 34.1 mm., height 26.6 mm., diameter 21.6 mm. 



Formerly a rare species in most collections, but now often obtained 

 by shrimpers fishing along the coast of Panama. 



Range — Coast of Mexico to Panama and Colombia. 

 Lophocardinm annettae (Dall) Plate 39, figures 2-2b 



Cardium {Lophocardium) annettae Dall, 1839, Nautilus, vol. 3, No. 2, p. 13 Lower 

 California near Cerros Island. — Dall, 1890, Proc. U. S. Nat. Museum, vol. 12, 

 p. 264, pi. 10, fig. 4.— Hertlein and Strong, 1947, Zoologica, vol. 13, pt. 4, p. 

 138, pi. 1, figs. 3, 8, 13. 



Shell thin, fragile, inflated, subovate, longer than high, gaping prom- 

 inently posteriorly. The color is usually a salmon or rose-red, sometimes 

 quite pale, heaviest over the posterior area, the surface covered by a paper- 

 thin periostracum. The surface sculpture is formed by numerous, small, flat 



