﻿190 I.AMPSII.IS 



Lami'Sims ni.ATciii,irvi Daniels. 



"Shell Ions', elliptical or obovate, compressed, tliin, inequilat- 

 eral, slig-htly ijapini^ behind ; beaks low, but little inflated, 

 pointed, with minute, nodulous sculpture ; dorsal and basal 

 outlines lightly curved ; anterior end somewhat narrowed, 

 rounded ; posterior end rounded, and lightly and obliquely 

 subtruncate above; surface with singular (regular?) growth 

 lines: epidermis somewhat concentrically wrinkled, projecting 

 beyond the border of the shell, yellow-green with faint green 

 rays ; pseudocardinals rudimentary, smooth, subcompressed ; 

 laterals straight, single in the right valve, partly double in the 

 left ; nacre brilliant, iridescent, having a somewihat coppery 

 lustre in the cavities, becoming ver\' thin and greenish at the 

 edges. 



Length 45, height 2\, diam. 10 mm. 



Length 40, height 17, diam. 8.5 mm. 



Soft parts: Marsupium very large, occupying the posterior 

 two-thirds of the outer gills, each lobe containing apparently 

 about forty narrow ovisacs, the whole rounded and projecting 

 well below the inner gills : inner gills united to the abdominal 

 sac throughout their length : ]iali)i large. elli])tical, projecting 

 backward but little : mantle much thickened on the border, its 

 edges being decidedly double wavy and dark colored ; branchial 

 opening rather large, with stout papill?e : anal opening small, 

 crenulate ; super-anal opening long, closed below ; foot rather 

 large." (Daniels). 



Type locality, Wabash River, Linn Township, Posey Co., 

 Ind. Also. Hardy, Ark. ( ?) and Iowa River. Iowa City, Ia.( ?) 

 Lampsilis blatchleyi DANnu.s, Naut., X\'I. i()02, p. 13, pi. 11. 



"The species is closely allied to /.. leptodon Raf., particularly 

 in its anatomical characteristics : the shell differs from that 

 species by not having the wing and by the posterior end being 

 rounded and in the full-grown shell being not more than one- 

 half the size.'' 



