284 AXEL A. OLSSON 



Hysteroconcha mnltispinosa (Sowerby) Plate 47, figures 2-2d 



Cytheraea multispinosa Sowerby, 1851, Thes. Conch., vol. 2, p. 632, No. 70, pi. 132, 



fig. 112 Tumbez, Peru; in soft mud, at ten fathoms "Tumbez, Peru." 

 Dione multispinosa (Sowerby), Reeve, Conch. Icon., vol. 14, Dione, pi. 6, fig. 22. — 



Romer, 1868, Monogr. Molluskengatung Venus Linne, vol. 1, 5 sectio: Dione 



Gray, pp. 132, 133, pi. 35, figs. 2, 2a, 2b, 2c. 

 Pilar {Hystcroconcha) lupanaria multispinosa (Sowerby), Maxwell Smith, 1944, Panamic 



Marine Shells, p. 60, fig. 774. 



Like H. lupanaria but smaller (50 mm. or less), longer ovate, the con- 

 centric riblets more numerous, thinner and higher along their whole length, 

 and generally sharp and harsh to the touch. Along the anterior submargin, 

 the alternate riblets are elevated into high, thin lamellae. The valves are 

 usually colored a grayish white, lightly stained with yellow, brown or violet, 

 never as strongly colored as H. lupanaria. Spines are large and slender. 



Length 40.1 mm., height 3L6 mm., diameter 24.5 mm. Bucaro, Panama. 



This species resembles H. dione (Linne) from the Caribbean but is 

 somewhat longer and has fewer, heavier, and more widely spaced concen- 

 tric riblets while the spines along the posterior angle are fewer in number. 



Range — Mexico to northern Peru. Panama: Bucaro; Guanico. Ecuador: 

 Limones; San Francisco, Peru: Tumbez, 



Hysteroconcha brevispinosa (Sowerby) Plate 47, figures 4, 4a 



Cytheraea brevispinosa Sowerby, 1851, Thes. Conch., vol, 2, p, 632, No. 71, pi. 132, fig. 



109 California? 

 Dione brevispinata Reeve, 1863, Conch. Icon., vol. 14, pi. 6, fig. 21. 

 Dione brevispinosa (Sowerby), Romer, 1868, Monogr. Molluskengatung Venus, Linne, 



bd. 1, 5 Sectio: Dione Gray, pp. 133, 134, pi. 35, fig. 3. 



Shell ovate, the beaks near the anterior one-third, subsolid, compressed 

 or slightly convex, white. Sculpture is formed by relatively large, foldlike 

 concentrics, even and uniform over most of the surface but near the pos- 

 terlor-umbonal angle occasionally divide or fork while on the anterior side, 

 the alternate ones become narrowly lamellose. The concentrics end abruptly 

 at the umbonal angle, their ends enlarged into short scales. Posterior- 

 dorsal slope flattened or slightly rounded, smoothlsh. 



Length 44.8 mm., height 37.7 mm., diameter 10 mm. (left valve, 

 Esmeraldas), 



Rare and local. I have seen specimens only from Ecuador and southern 

 Colombia. 



Range — Gulf of California to Ecuador, Colombia: Isla del Gallo. 

 Ecuador: Port Limones; Esmeraldas; Sua; San Francisco. 



Hystcroconcha rosea (Broderip and Sowerby) Plate 47, figures 3-3d 



Cytherea rosea Broderip and Sowerby, 1829, Zoo!. Jour., vol. 4, No. 15, p. 364 St. Bias. 



—Sowerby, 1839, Zool. Beechey's Voyage, p. 151, pi. 43, fig. 7.— Philippi, 1847, 



Abbild. und Beschreib, Conchylien, bd. 2, Cytherea, pp. 181, 182, No. 6, pi. 5, 



fig. 6. 

 Cytherea rosea Broderip and Sowerby, Sowerby, 1851, Thes, Conch., vol. 2, p. 132, No. 



68, pi. 132, fig. 108. 

 Dione rosea (Broderip and Sowerby), Reeve, 1863, Conch. Icon., vol. 14, Dione, pi. 7, 



fig. 29. — Romer, 1868, Monogr. Molluskengatung Venus, Linne, bd, 1, 5 Sectio: 



Dione Gray, pp. 134, 135, pi. 35, fig. 4. 

 Pitar {Hysteroconcha) rosea (Broderip and Sowerby), Maxwell Smith, 1944, Panamic 



Marine Shells, p. 60, fig. 755, 

 Pitar {Hysteroconcha) roseus (Broderip and Sowerby), Hertlein and Strong, 1948, 



Zoologica, vol. 33, pt. 4, No. 13, p. 174. 



