282 AXEL A. OLSSON 



Tlnctora Tulnerata (Broderip) Plate 45, figures 4, 4a 



Cytherea vulnerata Broderip, 1835, Proc. Zool. Soc. London, p. 46 Real Llejos. — 



Sowerby, 1851, Thes. Conch., vol. 2, p. 632, pi. 131, figs. 95, 96 (as Cytheraea). 

 Dione vulnerata (Broderip), Reeve, 1863, Conch. Icon., vol. 14, Dione, pi. 5, figs. 16a, 



16b. 

 Pitaria vulnerata (Broderip), Dall, 1902, Proc. U.S. Nat. Museum, vol. 26, p. 399.— 



MaxvFell Smith, 19+4, Panamic Marine Shells, p. 60, fig. 782. 

 Pilar {Tinctora) vulneratus (Broderip), Hertlein and Strong, 1948, Zoologica, vol. 33, 



pt. 4, No. 13, pp. 176, 177. 



Shell suborbicular, solid, moderately convex, with fine concentric ridges, 

 interspaced with deeper resting marks. The color of the surface is white or 

 cream, often pencilled or mottled with brown lines, best seen on the um- 

 bones, and the resting lines show often as deeper colored rings of violet 

 or purple. Interior white, porcellaneous, the ventral margins irregularly 

 Granulated. 



Length 47.6 mm., height 45 mm., diameter 29.9 mm. Holotype, British 

 Museum (Nat. Hist.). 



Range — Gulf of Cahfornia southward to Panama. Panama: Pearl 

 Islands. 



Genus HYSTEROCONCHA Dall. 1902 

 {Dione Gray, 1847, not of Hiibner, 1816, and others.) 



Type species by original designation, Venus dione Linne. Recent, Carib- 

 bean. 



The shell is ovate to trigonal, moderately convex to compressed, thin 

 or solid. The lunule is small, cordate, impressed, bordered by an incised 

 line, smooth, the escutcheon is less well defined and is represented merely 

 by a narrow, flat area without sculpture along the dorsal margin. The 

 hinge as in Pitar, the anterior lateral tooth placed near the cardinals. The 

 right anterior, cardinal tooth is small, narrow, and vertical, joined above 

 to the posterior, cardinal tooth to form a vault-like roof over the middle 

 cardinal tooth beneath it. The surface is neatly sculptured with evenly 

 spaced, concentric ridges of which the alternate ones become elevated or 

 lamellose on the anterior slope; on the posterior-umbonal slope, the con- 

 centric ridges end sharply while each third or fourth one is prolonged or 

 enlarged into a long, slender spine, or in some species ends in a short stump 

 or scale. The color is usually some shade of purple or violet, sometimes a 

 salmon-rose, more rarely completely white. Pallial sinus is large and ample, 

 extending to or beyond the middle of the valve. 



Key to species of Panamic-Pacific Hysteroconcha 



I. With lines of large spines on the posterior-dorsal slope, one row along 

 the umbonal angle, the other in the middle. 



1. Shell large, subovate in shape, the concentric riblets usually weak or 

 smoother across the middle of the disk. Color a violet-brown or purple, 



H. lupanaria 



2. Shell smaller, elongate ovate in shape, the concentric riblets more 

 elevated, lamellose, continuous across the disk, and rather harsh to the 

 touch. Surface less strongly colored. 



M. multispinosa 



