﻿ALASMIDONTA 507 



Alasmodon corrugata De Kay, Zool. of N. Y., Pt. 5, 1843, p. 



198, pi. XXIV, fig. 259. 

 Mya rugulosa Wood, Ind. Test., 3d ed., 1856, p. 199, pi. i, supp. 



fig. 7- 



Certainly distinct from the heavier, larger, more inflated 

 and truncated form found in western rivers. The teeth are 

 less developed and it is biangulate behind. Specimens oc- 

 casionally grow somewhat larger than the measurements given 

 above. 



Alasm]lx)nta raveneliana (I,ea). 



Shell oblong, subrhomiboid, scarcely inflated, thin to sub- 

 solid, inequilateral ; beaks moderately full, slightly elevated, 

 their sculpture apparently a few strong, somewhat doubly- 

 looped bars ; posterior ridge double, ending behind at or near 

 the base in a biangulation ; posterior slope having fine corrugat- 

 ■ed, radiating wrinkles ; surface otherwise generally smooth or 

 marked with a few uneven growth lines ; epidermis pale yel- 

 lowish-green to brown, faintly rayed, the rays sometimes brok- 

 en into blotches ; each valve has a single, low, smooth tooth 

 near the beaks ; laterals almost or quite obsolete ; nacre dirty 

 greenish, whitish or purplish, lurid ; prismatic border distinct. 



Tength 76, height 39. diam. 2 7, mm. 



Length 75, height 42, diam. T,y mm. 



Tennessee and Cumberland River Systems. 



Tvpe locality, French Broad and Swannanoa rivers, N. C. 

 Margaritana rai-eneliana Lea, Tr. Am.. Phil. Soc., V. 1834, p. 



106, pi. XVII, fig. 50; Obs., L 1834, p. 218, pi. XVII. fig. 50. — 



KusTER. Conch. Cab. l^nio, 1862, p.. 297, pi. xcix, fig. 2. 

 Alasmodov.ta niveneUmia Ferussac, Guer. Mag., 1835, p. 26. 

 Margarita (Margaritana) rarencUana Lea, Syn., 1836, p. 44; 



1838, p. 27. 

 Margaron (Margaritana) raveneliana Lea, Syn., 1852. ]). 42 : 



1870, p. 68. 

 Baphia raz'eneliana H. and A. Adams, Gen. Rec. Moll., IT, 



1857, p. 500. 

 Alasniidonta ra: eneliana Simpson, Syn., 1900, p. 671. 



