592 MOLLUSCA. 
H. Uhde, who lived for some time in Mexico, had a specimen of this species in his 
collection (7 8), without indication of locality ; this collection, however, also included a 
number of Cuban shells, and there is no reliable evidence that he found it in Mexico, 
as Fischer and Crosse 9 suggest. 
For fuller synonymy, see v. Martens ® and Fischer and Crosse ®. 
Neritina (Smaragdia) viridis. 
Nerita viridis, Linn. Syst. Nat. ed. 10, p. 778°; Lamarck, Hist. Nat.des Anim. sans Vert. éd. 1, vi. 
2, p. 188°; éd. 2, par Deshayes, viii. p. 577°; Sowerby, Conch. Illustr. no. 22, fig. 24°; 
Thes. Conch. ii. p. 582, t. 116. figg. 229, 280°; Reeve, Conch. Icon. ix. fig. 153°; v. Mart. 
in Martini & Chemnitz, Syst. Conch.-Cab. ed. 2, Neritina, p. 246, t. 4. figg. 14-19"; 
Fisch. & Crosse, Miss. Scient. Mex., Moll. ii. p. 490°. 
Smaragdia viridis, Issel, Ann. Mus. Civ. Stor. Nat. Genova, xi. p. 429 (1878) °; Troschel, Gebiss 
der Schnecken, ii. p. 183, t. 16. fig. 21”. 
Hab, EK. Mexico: Vera Cruz (Baker). 
Yucatan: Progreso (Baker). 
E. Costa Rica (Pittier 8). 
Not rare in the Mediterranean and in the Caribbean Sea, also at the Bermudas 
(Jones, 1859); truly marine, on sea-grass. 
POLYMESODA. 
See anted, p. 540. 
16. Polymesoda maritima. 
Cyrena maritima, C. B. Adams, Ann. Lyc. Nat. Hist. N. York, v. p. 499 (1852)'; Prime, 
Monogr. Am. Corbiculade, p. 27, fig. 20° [nec C. maritima, d’Orbigny (1846) in Sagra’s 
Hist. fis. polit. y nat. de Cuba, Mol. t. 26. figg. 47-49, = cubensis, Prime (1865), which is 
much nearer P. salmacida]. 
Hiab. 8. Panama: two and a half miles east of Panama, in impalpable mud, under 
bushes at high-water mark where a small stream emptied ; some of the dead shells 
have Balani growing upon them (C, B. Adams 12). 
“Like all the species of this genus which live in estuaries, it is almost entirely 
deprived of epidermis, some few remnants of it only existing on the margins of the 
shell” (Prime*, p. 28). The same is the case with the estuarine forms of Neritina. 
In the description, however, Prime? merely says: “ epidermis greenish-brown, worn on 
the upper portion of the shell.” C. B, Adams? describes it as having “an olivaceous 
coarsely striate epidermis.” The general form of the shell is more like that of a true 
Polymesoda than of a Cyrenocapsa ; but in the narrowness of the hinge-plate it agrees 
with the latter. 
