180 
231. Corbula nuciformisSow. Proc. 1833. p. 35. 
Reeve f. 9. — Sonsonate speeimen unicum. Long, 5, alt. 
3l/, mill. 
232. Corbula bicarinata Sow. Proc. 1833. p. 35. 
Reeve f.23. — Los Bocorones ad prof. 30 org. spec. 1!/,. 
Long. 10, alt. 71, mill. 
233. Thracia carnea Mörch. — T. elongata, an- 
gustata, pellucens carnea vel sordide rosea, planiuscula, 
valde inaequilateralis; margo dorsalis anticus longus cana- 
liculatus, subrectus, posticus declivis, brevis; antice oblique 
rotundata; margo ventralis rectus, postice ascendens; po- 
stice rostrata, oblique decisa, unde superne angulo obtuso, 
inferne acuto; umbone prominente acutiusculo; area carina 
obtusa circumscripta, carinula obsoletissima postice; striae 
inerementi huc illuc prominentiores, praesertim in area; 
prope umbonem concentrice plicatula, vix vestigio striarum 
adiantium; intus albescens. Valva sinistra dentibus duobus, 
antico prominente umbonali fusco, postico minutissimo. 
Sinus palliaris® Long. 113/,, alt. 8 mill. Tellina angu- 
lata Hanl. Thes. f. 107 quoad formam. — Golf di Nicoya 
valva solitaria sinistra, 
234. Mactra (Mactrella) exoleta Gray Mag. 
Nat. Hist. 1837. p.372. Reeve Icon, f. 16. Hanl. Suppl. 
pl. XL £. 51. — Realejo specimina 2 et valvulae solita- 
riae 9. 
Specimina nostra differunt testa antice rotundata et 
altitudine minore; epidermide lirulis radiantibus distantibus 
obsoletis vel in testam impressis. 
235. Mactra (Mactrella) subalata Mörch. — 
Mactra alata Spenel., Reeve f. 29. West - Columbia. — 
Realejo valva dextra solitaria trita. Long. 55, alt. 40 mill. 
Diftert aM. alata (M. bajana Gmel.): T. antice con- 
vexa, breviore late rotundata, lunula minus compressa, area 
costa unica obtusa nec trilirata. 
Ein Exemplar von Mactra alata Spengl., von Hrn. 
