Volume 2

Observations on the genus Unio / [Isaac Lea].

  • Isaac Lea
Date:
[1834-1874]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the genus Unio / [Isaac Lea]. Source: Wellcome Collection.

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    by being more regularly elliptical, and being smoother and polished. The nacre of Zeiglerianus, in several specimens before me, is pur¬ ple and salmon, some having a white margin. I presume the domi¬ nant colour to be purple. I have pleasure in dedicating this shell to F. Zeigler, a distinguished zoologist of Vienna. Unio creperus. Plate X. fig. 28. Testa subellipticd, transversissima, valtU incequilaterali; valvulis subcrassis; natibus pro- minulis, undulcitis; epidermide virkle; dentibus cardinalibus parvis; laleralibus vix cernendis; margaritd alba. Shell subelliptical, very transverse, very inequilateral; valves somewhat thick ; beaks rather prominent and undulated at tip; epidermis greenish ; cardinal teeth small; la¬ teral teeth obscure; nacre white. Hab. Tennessee. Professor Troost. My Cabinet Diam. 1, Length 1*4, Breadth 2*7 inches. Shell subelliptical, subemarginate at base, very transverse, very ine¬ quilateral, somewhat flattened over the umbones; substance of the shell thick anteriorly, thin and iridescent posteriorly; beaks rather ele¬ vated, retuse, and finely undulate at tip; ligament long; epidermis dark green and obscurely rayed; cardinal teeth small and elevated; lateral teeth obscure, being perceptible only at the termination; ante¬ rior cicatrices distinct; posterior cicatrices confluent; dorsal cicatrices in the centre of the cavity of the beaks; cavity of the shell deep; cavity of the beak small; nacre white. Remarks.—I owe to the kindness of Professor Troost the single valve which I possess of this species. It has some resemblance to the U. emarginatus (nobis), but perhaps resembles more the U. iris (nobis). In the structure of the teeth, particularly in the lateral tooth, the cha¬ racter is obscure. In this it resembles the U caiceolus (nobis). At the termination of the ligament there is, however, in my specimen, a
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