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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    Unio arctior. Plate IY. fig. 10. Testa angulato-ellipticd, valde transversa, compressa; valvulis subtenuibus; natibus com- pressis et undulalis; dentibus cardinalibus parvis; lateralibus longis; margarita alba et salmonis colore tincta. Shell narrow-elliptical, very transverse, compressed; valves rather thin; beaks compressed and undulated; cardinal teeth small; lateral teeth long; nacre white and salmon colour. Hab. Ohio River, near Cincinnati. T. G. Lea. My Cabinet. Cabinet of P. H. Nicklin. Cabinet of Professor Yanuxem. Cabinet of William Hyde. Diam. *7, Length 1*1, Breadth 2*3 inches. Shell narrow, elliptical, very transverse, subangular behind, flattened on the sides; substance of the shell rather thin; beaks compressed, un¬ dulated; ligament rather long and slender; epidermis dark brown, wrinkled; cardinal teeth very small; lateral teeth long, straight, and enlarged at posterior end; anterior cicatrices distinct; posterior cica¬ trices confluent; dorsal cicatrices situated on the plate between the cardinal and lateral teeth; cavity of the shell very shallow ; cavity of the beak shallow and subangular; nacre white, salmon colour, and sometimes purple. Remarks.—I have for some years been in doubt if this should be separated from the gihbosus of Barnes, of which it has generally been considered a variety. After proper examination, believing it to be dis¬ tinct, I propose to separate it from that species. It certainly very closely resembles the gihbosus, but may at once be distinguished by its being a smaller shell, and possessing much less substance. The gibbo- sus is generally purple; this species is usually white or salmon colour, but sometimes purple.
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