438 AXEL A. OLSSON 



Juliacorbnla elenensis, new species Plate 77, figure 5 



Shell of medium size and of moderate weight, oblong-ovate, sub- 

 equilateral and equivalve. The beaks are nearly central, the anterior side 

 is equal or only slightly longer than the posterior, well rounded at the end. 

 The dorsal margin along the posterior side descends at an angle of about 45 

 degrees terminating in an obtuse end. The rostrum is of moderate width, 

 bounded externally by a strong angle, along which, the concentric cords are 

 bent sharply; the rostral surface is flattened or a little arched, and borders 

 the margin; there is a narrow, smooth, depressed escutcheon. There is no 

 lunule. The surface is sculptured by a series of rather coarse, even, slightly 

 inclined concentrics set apart from each other by deeply grooved inter- 

 spaces. Color white or cream, the umbones often bordered by a white ray 

 on each side. 



Length 17 mm., height 12 mm., diameter of a right valve 4.2 mm. 

 Santa Elena, Ecuador. Holotype, ANSP 218913. 



This species resembles /. biradiata but is more convex, its sculpture 

 more regular, and it lacks the colored rays along the sides of the beak and 

 umbone. It differs from /. ecuabula by its more equilateral valves. It is 

 also similar to C. knoxiana (C. B. Adams) of the Caribbean, but is larger 

 than most specimens of that species, and its outline is longer and less 

 squared off at the ends. 



Range — Ecuador and Peru. Ecuador: Puerto Callo; Santa Elena. Peru: 

 Tumbez; Zorritos. 



Genus TARICORBULA Grant and Gale, 1931 

 Type species by original designation, Corbula gibba (Olivi). Mediter- 

 ranean Sea and west coast of Europe. Recent and fossil. 



Shell generally small, subtrigonal, the valves unequal in size and sculp- 

 ture, the right valve larger, convex, obtusely rostrated, the umbone high, 

 ending in an erect or prosogyrate beak curved over the hinge line, its sur- 

 face ornamented with strong, concentric sculpture; the left valve is much 

 smaller, depressed or flattened, smooth or with faint, widely spaced, radial 

 lines. 



Taricorbula speciosa (Reeve) Plate 77, figures 7-7c 



Corbula radiata Sowerby, 1833, Proc. Zool. Soc. London, p. 36. Not of Deshayes, 182+. 



"Hab. ad Acapulcam". 

 Corbula speciosa Reeve, 18+3, Conch. Icon., vol. 2, Corbula, pi. 1, fig. 6. (new name 



for C. radiata Sowerby) "Gulf of Nicoya". — Hinds, 1843, Proc. Zool. Soc. 



London, p. 57.— Hinds, 18+1, Zool. Voy. Sulphur, Moll., pt. 3, p. 68, pi. 20, 



figs. 7, 8. 



Shell rounded or trigonal ovate, inequivalve, the right valve much 

 larger than the left, convex, with coarse, undulate, concentric sculpture, 

 whitish, rayed with salmon pink or purple; the left valve smaller, longer, 

 more depressed and with finer sculpture, its color darker, rayed with reddish- 

 brown. Both valves have the umbones capped by a large, conspicuous, 

 nepionic shell, finely mottled or marbled with white and violet-brown 

 markings. Interior white with a narrow brown margin. 



Length 18.2 mm., height 12.3 mm. Gulf of Nicoya, British Museum 

 (Natural History). 



