PANAMIC-PACIFIC PELECYPODA 301 



Shell broadly subelliptical in shape, of medium thickness, convex. The 

 ventral margin is semicircular, the posterior end blunt, the anterior side 

 rounded and somewhat produced. The surface is beautifully adorned with 

 a series of high, thin lamellae (radially grooved on both sides) which extend 

 as continuous, elevated, lacelike frills from the edge of the lunule to the 

 dorsal margin; and in addition, a set of strong, paired, radial riblets cover 

 the wide, flat interspaces as well as on both siaes of the concentric lamellae. 

 On the umbones, the radials are simple but below they are mesially grooved 

 so as to appear double. 



Length 52.8 mm., height 44.6 mm., diameter 32.6 mm. 



This is the finest and most ornate species of the genus but Reeve's 

 figure in the Conchologia Iconica is poor and does not give full justice to 

 its striking beauty. In this connection, the following quotation from 

 Broderip's original description is of interest, "This unique and highly orna- 

 mented shell was dredged up from sandy mud at a depth of ten fathoms. 

 The radiating ribs, each of which, as it advances from about the middle of 

 the valve to the ventral border has a depression in the middle, and the 

 crisply plaited well-developed concentric frill-like lamellae, render it the 

 most curious in point of workmanship of any of the species." 



Several fine specimens of this species were obtained by Mr. Harry B. 

 Johnson, formerly of the Panama Canal Zone. The species is known as 

 fossil in the Pliocene of Panama and was described from there by Pilsbry 

 and Olsson as Chione traftoni. 



Range — Panama southward to Ecuador. Panama: Off Cape Mala 

 (shrimpers). Ecuador: Off Cabo Pasados, in 15 fathoms (Hertlein and 

 Strong). 



Chlonopsis pnrpnrissata (Dall) Plate 52, figure 3 



Fenus crenulata var. Reeve, 1863, Conch. Icon., vol. 14, Venus, pi. 13, fig. 46. (Not V, 



crenulata Sowerby, 1853=C. pubera Valenciennes, 1827) Gulf of California. 

 Venus crenulata var. lilacina Carpenter, 1864, Rept. Brit. Assoc. Adv. Sci. for 1863, p. 



570, No. 46. Reprinted 1872, Smith. Misc. Coll., No. 252, p. 56. (Not Chione 



lilacina Gray, 1838.) 

 Chione {Chione) purpurissata Dall, 1902, Proc. U. S. Nat. Museum, vol. 26, No. 1312, 



p. 393. (New name for C. lilacina Carpenter, 1864.) 

 Chione {Chionopsis) purpurissata Dall, Hertlein and Strong, 1948, Zoologica, vol. 33, 



pt. 4, p. 185. 

 Chione (Gnidiella) purpurissata (Dall), Parker, 1949, Jour. Paleont, p. 584, pi. 91, 



fig. 2, 15; pi. 93, fig. 13. 



This beautiful species, with the interior of the disk rosepurple, was 

 figured by Reeve as a variety of Venus crenulata of the West Indies (by 

 \yhich Chione pubera Valenciennes is meant), and was named variety 

 lilacina by Carpenter, 1864; but it is not Chione lilacina Gray, 1838, and so 

 a new name is proposed for it. It is a rounder shell than C. pubera, with 

 less prominent lamellation, especially on the posterior slope, which, in this 

 species, is often wholly destitute of lamellae. (Dall, 1902.) 



Shell roundly trigonal, rather tumid, posterior end rounded; orna- 

 mented by rather fine radial and concentric sculpture; lunule large, orna- 

 mented only by lines of growth; a shallow and rather narrow radial de- 

 pression occurs posteriorly just above the escutcheon which is large and 



