PANAMIC-PACIFIC PELECYPODA 351 



Tagelus (Tagelus) dombeii (Lamarck) Plate 62, figures 1, la, 5 



^olen dombeii Lamarck, 1818, An. s. Vert., vol. 5, p. 454. — Lamarck, Encyl. Meth., pi. 



224, fig. 1.— Hupe, 1854, Hist, de Chile, vol. 8, Moll., p. 366. pi. 7, fig. 5. 

 Siliquaria dombei (Lamarck), Martinez y Saez, 1879, Hidalgo, Molluscos del Viaje al 



Pacifico. Parte Segundo, Bivalvos Marino, p. 7, pi. 1, fig. 4. 

 Tagelus (Mcsopleura) dombeyi (Lamarck), Dall, 1910, Proc. U.S. Nat. Museum, vol. 



37, pp. 160, 273, pi. 27, fig. 3. 



Shell narrowly elongated, the dorsal and ventral sides parallel, the 

 ratio of height to length nearly 1 to 4. The valves are moderately convex 

 and slightly flattened across the middle zone, the ventral margin straight 

 or weakly inflected. Color over most of the surface is a rusty brown, deepest 

 on the umbones and with two, narrow white rays extending obliquely back- 

 wards from the beak, the posterior and anterior ends often shaded lightly 

 with violet; also in the interior. The pallial sinus is deep but does not reach 

 the middle of the shell cavity. Periostracum coarse and heavy, coarsely 

 wrinkled and dark brown in color. Valves are widely open at both ends. 



Length 90 mm., height 25.3 mm., diameter 16 mm. Tumbez, Peru. 



This is the common Tagelus in Peru recognized by its relatively long 

 shell, rayed umbones and purple coloration of its two ends. It has no internal 

 ray or rib radiating from the beak even in young specimens. 



Range — Panama southward to Chile. Panama: El Lagartillo. Colombia: 

 Isla del Gallo. Ecuador: Canoa; Santa Elena. Peru: Tumbez; Negritos; 

 Bayovar. 



Tagelus (Tagrelns) affinis (C. B. Adams) Plate 62, figures 4, 4a 



Solecurtus affinis C. B. Adams, 1952, Ann. Lyceum Nat. Hist. New York, vol. 5, op. 



524, 548, No. 510 Panama.— Turner, 1956, Occas. Papers on Mollusks, Mus. 



Comp. Zool. vol. 2, No. 20, p. 29, pi. 19, figs. 17, 18. 

 Tagelus {Tagelus) affinis (C. B. Adams), Hertlein and Strong, 1950, Zoologica, vol. 



35, pt. 4, No. 19, p. 222, pi. 1, figs. 9, 11. 



Shell elongate, the dorsal and ventral sides subparallel, the small, in- 

 conspicuous beak placed a trifle closer to the anterior side, the ratio of 

 height to length nearly 1 to 3. Both ends are well rounded, gaping, the pos- 

 terior-dorsal slope appearing a little depressed, the mid zone of the disk 

 flattened to slightly depressed. External surface beneath the periostracum 

 white, marked with growth incrementals generally coarser on the sides. 

 Teeth and nymphal plate small. Periostracum is usually worn off the um- 

 bones, elsewhere it is a thin, light brown to straw-colored, smoothly wrinkled, 

 generally with coarse, open reticulated meshlike wrinkles on the ends. In- 

 terior white, often porcellaneous, with the pallial sinus large and extending 

 to about the middle. Measurements of average specimen: length 58.7 mm., 

 height 21.4 mm., diameter of a single valve 6.8 mm. Another double-valved 

 specimen: length 55 mm., height 18.5 mm., diameter 11.5 mm. 



Range — Mexico to Ecuador. Panama: Panama City. Colombia: Isla del 

 Gallo. Ecuador: Esmeraldas; Sua. 



Tagelus affinis longisinuatus Pilsbry and Lowe 



Tagelus affinis longisinuatus Pilsbry and Lowe, 1932, Proc. Acad. Nat. Sci. Philadelphia, 

 vol. 84, p. 91, pi. 11, figs. 4, S Mazatlan. 



Specimens from Negritos, Peru, seem referrable to this subspecies. 

 They are longer and narrower than the typical form of T. affinis. A speci- 



