POLYMESODA. . 547 
Species imperfectly known, but with precise localities. 
7. Polymesoda pullastra. 
Polymesoda (Egetaria) pullastra, Morch, in Malak. Blatt. vii. p- 194 (1860-61) *.~ 
Cyrena pullastra, Prime, Monogr, Am. Corbiculade, p. 26; Bull. Mus. Comp. Zool. v. p. 43, t. 2. 
figg. 3 a, 6, c (1878) *, 
Very unequilateral, rounded before and behind, ventral margin much arcuated. 
Long. 30, alt. 23, diam. 15 millim. Vertices in 3 long. 
Hab. W. Nicaraaua: Realejo (Girsted 12), 
The typical specimen in the Museum at Copenhagen, figured by Prime, is very worn ; 
no other is known. 
8. Polymesoda exquisita. 
Cyrena exquisita, Prime, Ann. Lyc. New York, viii. p. 417 (1867 ye. 
Long. 24, alt. 22, diam. 12 millim. . 
Hab. S. Panama: Rio Chepo}. 
9. Polymesoda germana. | 
Cyrena germana, Prime, Ann. Lyc. New York, viii. p. 415 (1867) *. 
Long. 43, alt. 38, diam. 24 millim. . 
Hab. N.K. Mexico: Rio Panuco, near Tampico 1. 
Species of uncertain origin, but recorded as from Central America. 
10. Polymesoda acuta. 
Cyrena acuta, Prime, Journ. de Conch. ix. p. 355 (1861)*; x. p. 387, t. 14. fig. 1 (1862) ?; 
Monogr. Am. Corbiculade, pp. 21, 22, fig. 17* [nec C. acuta, R. Ludwig, Paleontographica, 
Vili. p. 197 (1861),= Corbicula faujasi, Desh., a Miocene fossil species]. 
Hab. Centra, AMERICA, without nearer indication of locality (Prime 1°), 
Very near P. placens, but apparently with a distinct angular line descending from 
the summits backward to the hinder end of the ventral margin ; the pallial sinus, too, 
is described as being “ narrow, curved, and acute at extremity.” 
11. Polymesoda sordida. . 
Cyrena sordida, Hanley, P. Z. S. 1844, p. 159°; Catal. Rec. Bivalv. p. 352, t. 14. fig. 517; 
Deshayes, Catal. Conchifera Brit. Mus. ii. p. 255°; Prime, Monogr. Am. Corbiculade, 
- p. 18% 
69* 
