Monography of the family Unionidæ : or, Naiades of Lamarck (fresh water bivalve shells) of North America ... . n the Alabama river; very large and fine in therivers of Tennessee. 18 This species in some of its varieties so nearly re-sembles U. heros, of Say, when the latter is old anderoded on the umbones, that Mr. Say at one timeconsidered them identical; the young shell of the he-ros, however, was found to be so entirely dissimilarto the young of the costatus, that the specific differ-ence was obvious to the most careless observer, andMr. Say in his synonymy retains his species. Thiscircumst
Monography of the family Unionidæ : or, Naiades of Lamarck (fresh water bivalve shells) of North America ... . n the Alabama river; very large and fine in therivers of Tennessee. 18 This species in some of its varieties so nearly re-sembles U. heros, of Say, when the latter is old anderoded on the umbones, that Mr. Say at one timeconsidered them identical; the young shell of the he-ros, however, was found to be so entirely dissimilarto the young of the costatus, that the specific differ-ence was obvious to the most careless observer, andMr. Say in his synonymy retains his species. Thiscircumstance should induce those naturalists wholive in favourable situations to study the young ofevery species, for as Mr. Lea has justly observed,they are the most certain guides to specific distinc-tions; when the umbones and beaks are perfect, mostspecies will exhibit very nearly the prominent cha-racters of the very young shells, and hence the ne-cessity of procuring cabinet specimens of the mostperfect description, if we would effectually trace thespecies and make ourselves acquainted with
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Keywords: ., bookcentury1800, bookdecade183, booksubjectmollusks, bookyear1836
