454 AXEL A. OLSSON 



Subgenus PANDORA s.s. 

 The right valve has one or two crural laminae; an erect, buttress-like 

 plug under the beak, and a posterior one set at an angle to the margin. 

 An anterior lamina may be present in the left valve. Surface smooth or 

 showing growth lines only. 



Pandora (Pandora) uncifera Pilsbry and Lowe Plate 81, figure 4 



Pandora unc'ifcra Pilsbry and Lowe, 1932, Proc. Acad. Nat. Sci. Philadelphia, vol. 84, 



pp. 104, 105, pi. 17, figs. 17, 18, 19. 



Pandora (Pandora) uncifera Pilsbry and Lowe, Hertlein and Strong, 1946, Zoologica, 



vol. 31, pt. 3, No. 8, p. 97. 



Shell small, elongate, strongly compressed, inequilateral, and inequi- 

 valve, the left valve larger, its ventral margin folded over that of the right. 

 Right valve has two obliquely set crural teeth; the first, just below the beak, 

 is relatively short and stout, the other on the posterior side, is long and 

 narrow; the ligament lies between them. The posterior-dorsal margin is 

 straight in the forward section, then somewhat concave, its end truncated. 

 The anterior-dorsal margin has a deep, hook-shaoed cut. Surface smooth. 



Length 12.4 mm., height 5.5 mm., diameter 1.3 mm. Type ANSP. 



The hook-shaped cut along the anterior-dorsal margin is characteristic. 

 The species is related to P. brevifrons Sowerby but differs by its broader 

 outlines. 



Range — Mexico southward to Ecuador. Mexico: Acapulco (Pilsbry and 

 Lowe); Gorda Banks, Port Guatulco, Tangola Bay (Hertlein and Strong). 

 Costa Rica: Port Parker (Hertlein and Strong). Ecuador: Manta. 



Pandora (Pandora) brcrifrons Sowerby Plate 81, figure 5 



Pandora brevifrons Sowerby, 1835, Proc. Zool. Soc. London, p. 93 Panama. — Sowerby, 

 1855, Spec. Conch., vol. 1, pt. 2, Pandora pi. not numbered, figs. 25, 26. — 

 Sowerby, 1874, Conch. Icon., vol. 19, Pandora, pi. 2, fig. 12. 



Shell thin, elongate, the length nearly three times the height, inequi- 

 valve, the left valve larger, convex, overlapping the smaller, depressed or 

 flattened right valve along the ventral margin. Beaks are strongly anterior. 

 Surface smooth, the growth lines hardly visible. Posterior-dorsal submargin 

 with two, rounded or obscure keels. 



Length 24.8 mm., height 9.6 mm. Panama. ANSP 55372. 

 Range — Panama. Panama: Panama. 



Subgenus PANDORELLA Conrad, 1863 

 {Kennerlia Carpenter, 1864, emendations: Kennerleya Fischer, 1887 

 and Kennerlyia Dall, 1903). 



Type species by monotypy, P. {Pandora) arenosa Conrad. Miocene of 

 Virginia. 



Shell like Pandora, s.s. the hinge having two crural elements in the 

 right valve but with the resilium heavily reinforced by a lithodesma. Surface 

 of the right valve marked with radial grooves. 



Conrad's name has priority over that of Carpenter by about one year 

 but until the hinge of the type species, P. arenosa is better known, the 

 equivalence of Pandorella with Kennerlia remains doubtful. 



