﻿l86 I.AMl'SIMS 



Aniiiuil with large, elliptical palpi; mantle slightly thickened 

 at the edge; anal opening widely separated from the superanal, 

 the latter large ; foot large, hatchet-shaped. Several animals 

 were examined, but all were so much decayed that most of the 

 characters could not be made out. 



Lampsh.is AMi'iiicii.^iNA Frierson. 



Shell large, long elliptical, subintlated, subsolid, with moder- 

 ately full, but not high, beaks, whose sculpture has not been 

 seen ; with a long, narrow gape on the anterior base and a most 

 decided one behind just above the posterior point ; posterior 

 ridge full, rounded; surface with irregular growth marks; 

 epidermis dark brown to jet black, smooth and shining on the 

 middle of the disk, somewhat roughened and lamellar on the 

 rest of the shell, especially on the posterior slope ; left valve 

 with one rather feeble, subcompressed pseudocardinal and a 

 vestigial second one in front of and below it, with two short, 

 very remote laterals ; right valve with one pseudocardinal, 

 sometimes with a smaller one above it, and a remote lateral, 

 whose inner edge is curved upward ; beak cavities shallow, with 

 an irregular row of large muscle scars running down towards 

 the anterior base ; anterior scars large, shallow ; posterior scars 

 small, somewhat elongated; pallial line wide, with a distinct 

 sinus behind ; nacre bluish and purplish, somewhat clouded. 

 The female shell differs but slightly from that of the male, 

 being a little fuller just behind the middle of the base and hav- 

 ing the blunt posterior point a trifle higher. 



Length 120, height 70, diam. 45 mm. The above measure- 

 ments are from a large male shell. 



Type locality, Saline River, Texas. 

 Unio (Lampsilis) amphichccnus Frierson, Nautilus, XI, 1898, 



p. 10, pi. I. 

 Lampsilis amphichccnus Simpson, Syn., 1900. p. 575. 



This is really a remarkable species, the great and distinct 

 posterior gape resembling that of a Schicothccnis niittalli. In 

 the specimen, whose measure is given above, it is about 10 

 millimeters wide. The anterior basal gap is narrower but ex- 



