WEST AMEKICAlir PYKAMIDELLID MOLLUSKS. 125 



Prof. C. B. Adams's type lot of Chemnitzia clathratula in the Amherst 

 collection contains two specimens of this species. His type lot of 

 Chemnitzia communis contains another specimen. Both lots are 

 from Panama. 



Named for Prof. Lancelot W. Andrews. 



TURBONILLA (DUNKERIA) ARATA, new species. 

 Plate 12, fig. 12. 



Shell large and rough. (Nuclear whorls decollated.) Post- 

 nuclear whorls somewhat inflated and overhanging, appressed at the 

 summit, well rounded, with the greatest convexity on the anterior 

 third between the sutures; marked by strong, narrow, rounded, well 

 raised, retractive axial ribs, of which 18 occur upon the first four, 20 

 upon the fifth, 22 upon the sixth and seventh, 24 upon the eighth, 26 

 upon the ninth, and 28 upon the penultimate turn. Intercostal 

 spaces about twice as wide as the ribs, marked by very deep pits, which 

 leave the intervening spaces as strongly elevated cords, nine of which 

 occur between the sutures. Of these cords the second and fifth below 

 the summit and the first above the periphery are of equal width and 

 wider than the rest; the first, which forms the summit, and the three 

 posterior to the one at the periphery are again of equal width; the 

 third and fourth below the summit are a little more slender than the 

 rest; the pit at the periphery and those that bound the fifth cord are 

 a little wider than the rest; the first and second below the summit 

 and the second and third pit above the periphery are equal and those 

 between the third and fourth cords are also equal. Sutures well 

 impressed. Periphery of the last whorl inflated. Base well rounded, 

 marked by the feeble continuations of the axial ribs and eight almost 

 equal incised spiral lines. Aperture large, oval; posterior angle 

 acute; outer lip somewhat flaring in its middle; columella slender, 

 curved, and slightly re volute. 



The type (Cat. no. 206890, U.S.N.M.) was dredged off Santa Cata- 

 lina Island, California. It has twelve post-nuclear whorls and meas- 

 ures: Length 10.2 mm., diameter 2.4 mm. 



TURBONILLA (DUNKERIA) GENILDA, new species. 

 Plate 12, fig. 2. 



Shell elongate-conic, white on the shoulder, the rest light brown. 

 (Nuclear whorls decollated.) Post-nuclear whorls flattened in the 

 middle, well contracted at the sutures, with a strong sloping shoulder 

 which extends over the posterior third between the sutures, rendering 

 them angulated at its anterior termination. The whorls are marked 

 by strongly elevated, narrow, axial ribs, which are vertical on the early 

 whorls and decidedly retractive on the later ones. Intercostal spaces 



