

590 MEMOIRS OF THE CARNEGIE MUSEUM. 



Glaharis crispatus Simpson, 1900, p. 919. 

 . Type-Zoca/i^?/..— South America?) ' "^ 



Other Localities. — Cayenne (Lea, Syn., 1870, p. 106); Amazon River (Sowerby, 



t.^^^1' -fr*^'^ reticulatus) . 



'^■" New Locality. — Rio do la Paila, Paila, U. S. of Colombia (C. H. Eigenmann 



coll., 1912). About twenty specimens, ton of them with soft parts, males and 



females. (The Rio de la Paila is a tributary of the upper Rio Cauca of the Rio 



Magdalena-drainage) . 



Distribution. — Simpson says that this species is widely distributed in tropical 

 South America, though but few exact localities are known. 



Characters of the Shell. — Of medium size (maximum length 67 mm.), moder- 

 ately thick, rather thin when young. Outline elongated subtrapezoidal, or sub- 

 elliptical. Height 52 to 61 pr. ct. of the length. Valves practically closed, or very 

 little gaping in front. Dorsal margin straight, or prevalently very gently curved 

 behind the beaks, descending in front of the beaks, and passing gradually into 

 the anterior margin. Posteriorly it forms a blunt angle with the posterior margin, 

 or passes into it in a curve. Posterior margin curved, obliquely descending in 

 its upper part, becoming gradually steeper, and sometimes nearly vertical at the 

 posterior end, which is blunt and rounded, but bends rather suddenly into the 

 lower margin. The posterior end is thus very little elevated above the base-line, 

 often practically at its level. Lower margin straight for a considerable distance, 

 often even slightly concave in the middle, gently sloping upward toward the front 

 and curving up into the anterior nKirgin. This ascending part, and the descending 

 anterior upper margin, make the anterior end of the shell narrower, but the whole 

 shell does not appear very oblique. The highest part of the shell is in the posterior 

 section. 



Valves moderately convex, rather flattened upon the sides, and sometimes 

 even with a shallow depression corresponding to the emargination of the lower 

 margin. Posterior ridge broad and rounded, indistinct, but the greatest diameter 

 of the shell (31 to 38 pr. ct. of length) is situated upon it, so that the shell is more 

 swollen posteriorly than anteriorly. Posterior slope slightly compressed, sometimes 

 with a very faint radial groove. Beaks not swollen and not elevated above the 

 hinge-line, located at 27 to 33 pr. ct. of the length. Lunula indistinct or narrow, 

 not very long. 



Epidermis finely wrinkled all over, the wrinldes partly concentric, but pre- 

 vailingly arranged in a radial pattern. Concentric and lamellar wrinkles are found 

 chiefly near the margins. Upon the disk, the pattern varies in the anterior and 



