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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    well defined terminal point of the lateral tooth, and in other speci¬ mens this may be found to be more developed. The anterior lobe of the cardinal tooth is conical. Unio glaber. Plate X. fig. 29. Testa elliptica, transversd, compressa, glabra, inoequilaterali; valvulis tenuibus; natibus subprominulis, undulatis; epidermide luted, radiata; dentibus cardinalibus parvis, elevatis; lateralibus longis ; margaritd alba. Shell elliptical, transverse, compressed, smooth and shining-, inequilateral; valves thin ; beaks somewhat prominent and undulated; epidermis yellow, radiated ; cardinal teeth small and elevated; lateral teeth long; nacre white. Hab. Holston River, Ten. Professor Troost. My Cabinet. Cabinet of Professor Troost. Diam. *5, Length *8, Breadth 1*5 inches. Shell elliptical, transverse, compressed, polished, somewhat com¬ pressed behind, inequilateral, substance of the shell thin, somewhat thicker before; beaks somewhat prominent, with fine, nearly parallel undulations at the tip; ligament short; epidermis smooth, yellow, with numerous fine rays nearly over the whole disk; cardinal teeth small, rather compressed, elevated; lateral teeth long; anterior cicatrices dis¬ tinct; posterior cicatrices confluent; dorsal cicatrices placed in the centre of the cavity of the beaks and under the cardinal tooth; cavity of the shell shallow; cavity of the beaks small, angular; nacre white and iridescent. Remarks.—Among the shells brought by Professor Troost from his geological exploration of the eastern part of Tennessee, was this one from the Holston. It is allied to U. iris (nobis), but is not so trans¬ verse. It differs also somewhat in the rays and beaks, and the epider¬ mis is more yellow. The epidermis is smooth and polished; in these respects it resembles the young of U. luteola (Lam.), siliquoideus (Bar.).
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