— 40 — 



Hlesodei^iiia Desm. 1830. Enc. meth. III. p. 441. et 1835. 

 Lamck. Hist. ed. 2a VI. p. 131. 

 Etym. fieoos, mediiis^ dso^iog , ligamentiim. 

 Mactraceormn genus. Typus: Mya Novae Zelandiae 



Chemn. 

 Adoptant Ouoy et Gaim. 1834. Voy. Astrol. Zool. 

 III. p. 504. 

 Agass. 1839. Moul. de Moll. p. 39. — in Mac- 



traceis. , 



Pariter Reeve 1841. Conch. syst. I. p. 63. 

 Hanley 1844. 111. catal. I. p. 38. 

 Thorpe 1844. Brit. Mar. Concb. p. 53. 

 Philippi 1844. Moll. Sic. II. p. 29. 

 Catlow 1845. Conch. Nom. p. 16. 

 Gray 1844. Revue zool. p. 407. — genus Mesodes- 



midarum. 

 PoT. et MicH. 1844. Gal. II. p. 206. — in Nym- 



phaceis. 

 LovEN 1846. Ind. Moll. Scand. occ. p. 42. 

 = Donacilla Lamck. 



9Ie»odeismiflae Gray 1840. Syn. Brit. Mus. * et1844. Rev. 

 zool. p. 407. 

 Etym. praec. 

 Familia Bivalvium. Genus: Mesodesma. 



Mesoclon Rafin. 1831. Enum. and Account. * > Fer. 1835. 

 Bull. zool. p. 93. 

 Etym. f.iEO0s, mediusj odovg, dens. 

 Ab Ilelice separatum genus. Typus: Helix thyroi- 



dus Say. 

 Beck 1837. Ind. p. 22. — subdivisio Tridopsis. 



IfleHoiiipliix. Rafiin. 1819. Journ. de phys. tom. 88. p. 425. 



(nec Mesomphyx.) 

 Etym. ? Vocab. deprav. : /leoog, medius; Ofi(pal6g, 



nmbilicMS. 

 Al) Helice disjunctum genus. Typus: Ilelix laevi- 



ffata Raf. 



