ART. 17 SHELLS FROM BRAZIL AND URUGUAY— MARSHALL 3 



with a row of muscle scars deeply punched. Nacre faded and 

 diseased, evidently white when normal. Pallial line well marked, 

 located about 10 mm. above the ventral margin. 



The type (Cat. No. 368237, U.S.N.M.) measures: Length, 97 mm.; 

 height, 53 mm. ; diameter, 30 mm. It comes from Canada Grande, 

 Department of Cevro Largo, Uruguay, and was presented by Dr. 

 Florentino Feiippone. 



This species vvill for tlie present stand by itself, as it shows but 

 little relationship to any species hitherto described. The beaks are 

 deeply eroded and but little may be said of their characters. The 

 right beak gives indications that its sculpture consisted of five or six 

 ve'^y strong^-adiating ribs. In form the shell is very similar to many 

 specimens of the common Anodoiita cafaracta Say of the eastern 

 United States. If lying with a lot of that species it would pass as a 

 slight variation of it. 



The species is named in honor of Dr. H. A. Pilsbry. 



ANODONTITES ELFA, new species 

 Plate 4. figures 4-6 



Shell rather small and thin, ovate-elliptic, narrow and rounded in 

 front, broad and obtusely pointed at the rear. Dorsal edge nearly 

 straight, rounding into the anterior margin, and joining the posterior 

 margin in a very obtuse angle. Beaks set about 16 mm. behind the 

 anterior end, and 40 mm. in front of the posterior end. General 

 surface of the shell rounding to the margins without making a dis- 

 tinct ridge at either end. Descent to the posterior margin gradual; 

 to the anterior margin rather abrupt. Sculpture of concentric growth 

 striae and several more distinct lines indicating rest periods, and 

 hints of radiating ruffles. Periostracum smooth and glossy at the 

 front and middle of the shell, posterior area much roughened by 

 lamellae of fugacious periostracum. Color bipartite, rich dark chest- 

 nut anteriorly, lighter chestnut posteriorly, the line of separation of 

 the two tints running from tlie beak to the middle of the ventral 

 margin. Interior much faded and chalky, but evidently greenish 

 in c^lor and with apparent radiating striae. Anterior adductor 

 scars lightly impressed, posterior scars superficial. Prismatic mar- 

 gin very broad near the anterior end of the ventral margin and here 

 the interior is flattened instead of concave. Pallial line about 6.5 

 mm. above the ventral margin. 



The type (Cat. No. 368998, U.S.N.M.) measures: Length, 56 mm.; 

 height. 32 mm.; diameter, 18 mm. It comes from Canada (irantle, 

 Department of Cerro Largo, Uruguay and was presented by Doctor 

 Feiippone. Cat. No. 368999, U.S.N.M., includes one right valve and 

 one left valve, not mates, from the same locality. Cat. No. 335740, 



