104 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 23 



Pecten purpuratus Lamarck. Sowerby, 1842, p. 52, pi. 15, fig. 113; pi. 



16, figs. 123-125. Callao Bay, Peru. 

 \non\ Pecten purpuratus Lamarck. De Kay, 1843, p. 174. "Southern 



coast [Atlantic, U.S.A.]." [= Ostrea gibba Linne.] 

 Pecten purpuratus Lamarck. Kiister, 1859, p. 78, pi. 20, figs. 1-3. Peru 



and Chile.— Dall, 1909, p. 149, pi. 26, figs. 5, 6. "From Coquimbo, 



Chile, northward to Ecuador." — Bosworth, 1922, p. 178, pi. 25, 



fig. 9. Pleistocene of NW Peru. 

 Pecten (PlagiocteniumJ purpuratus Lamarck. Hertlein, 1925, p. 14, pi. 



1, fig. 1 ; pi. 4, figs. 2, 4. Pliocene and Pleistocene of Chile. [Recent 



range same as Dall, 1909.] 

 Pecten (Aequipecten) purpuratus Lamarck. Grant & Gale, 1931, p. 



207, pi. 4, figs. 2a-2c. Pliocene of San Fernando, California. [Also 



previous Pliocene, Pleistocene and Recent records.] 

 Pecten purpuratus Lk. Pilsbry & Lowe, 1933, p. 139. "San Juan del 



Sur [Nicaragua] and Montijo Bay [Panama] ; dredged alive at 



Taboga Island [Panama] ; Corinto [Nicaragua]." 

 Chla?nys (PlagiocteniumJ purpuratuni (Lamarck). Bavay, 1936, p. 



315. 

 Holotype: Museum National d'Histoire Naturelle, Paris. 

 Type locality : Here designated Callao, Peru. 



Original description : P. testa alba, purpureo et nigro purpurascente 

 varia ; radiis 26, convexis ; intus zona purpureo-nigricante. 



Habite les mers orientales et australes. Mus. no. Mon cabinet. 

 Espece rare et tres-belle. Ses oreillettes sont un peu inegales. Largeur, 

 112 millimetres. On le dit du Japon. 



Additional description: Shell large, adult specimens averaging 105 

 mm in height and 120 in length; disk nearly circular, occasionally slight- 

 ly oblique; moderately convex, left valve more so than right; hinge line 

 more than half length of disk; auricles slightly unequal, either anterior 

 or posterior being longer. Right valve with 19 to 26 broad and fiat- 

 topped ribs, smooth on top except for very fine concentric lines of growth, 

 and with profusely lamellated ridges along sides; interspaces narrower 

 and prominently lamellated, especially near ventral margin, lamellae 

 occasionally forming low central ridge near margin. Anterior auricle 

 with 3 to 5 imbricated riblets ; byssal notch narrow and moderately deep, 

 with ctenolium of 4 to 8 teeth. Posterior auricle squared, truncated, or 

 with shallow sinus ; 7 or 8 radiating ridges ; entire auricle concentrically 

 striated. Left valve with profusely lamellated ribs, fringed along sides; 

 interspaces narrow, strongly lamellated, and with central ridges prom- 



