ART. 16. NEW FRESH WATER MUSSELS MARSHALL. 7 



the shell, and of a livid, slightly greenish hue, minutely granulous. 

 Siinulus very large, distinctly hooked at its lower end. 



The type (Cat. No. 339954, U.S.N.M.) measures: Length 50 mm., 

 height 35 mm., diameter 17 mm. It comes from Guaremales, Vene- 

 zuela, and was collected by Dr. Henry Pittier of the United States 

 Department of Agriculture. This species is named in honor of Dr. 

 Henry Pittier, whose explorations in tropical America have greatly 

 enriclied the National Museum's collections. 



This species classifies next to A. tortilis Lea, of which A. luteolus 

 Lea and A. scliomhurgianus Sowerby are supposed to be synonyms. 

 A. pitfieri has a more chunky form, a pinkish nacre instead of bluish, 

 has a prismatic border about three times as wide and has a much 

 larger sinulus which has a distinct hook at its lower end. The an- 

 terior adductor scars of tortilis are deeply impressed, while those of 

 pitfieri are entirely superficial. 



ANODONTITES COLOMBIENSIS, new species. 



Plate 1, fig. 5 ; plate 2. figs. 13. 14 ; plate 3, figs. 5, 13, 14. 



Shell large, thick, elongate, moderately inflated, prominently con- 

 stricted from the beaks to the ventral margins. The ventral mar- 

 gins deeply incurved, valves widely gaping from the point of con- 

 struction of the ventral margin to the anterior end. Dorsal margin 

 regularly and highly arched, posterior portion of the shell elongated 

 and drawn obliquely downward. Both ends regularly rounded. 

 Posterior dorsal ridge inflated, rounded, with no indication of an 

 angular tendency. Periostracum thick, dull, cloth-like, closely ad- 

 liering. Entire surface roughened by many fine irregular wrinkles 

 and puckers radiating from the beaks. A similar wrinkling is ob- 

 scurely seen in the nacre, especially in the portion between the 

 mantle scar and the ventral border. Color uniform dark chestnut 

 with several radiating green stripes on the posterior dorsal area. 

 Interior dull, very slightly pearly, livid, with touches of green in 

 the posterior portion and salmon-colored tints in the deeper por- 

 tion of the valves, the remainder bluish. Anterior adductor scare 

 deeply impressed, posterior scars well impressed but not deep. 

 Sinulus rather large with a distinct hook at its lower end. Pris- 

 matic border narrow, widest at the posterior ventral end, of a dark 

 olive green color. 



The type (Cat. No. 341472, U.S.N.M.) measures: Length 82 

 mm., height 37 mm., diameter 26 mm. It and three other specimens 

 come from a tributary of the Eio Colorado in the Province of San- 

 tander. United States of Colombia, and was collected and presented 

 by Dr. C. Wythe Cooke. The Rio Colorado becomes tributary to 

 the Rio Magdalena and is in the Caribbean drainage system. This 



