Vol. XXIll, pp. 171-172 December 29, 1910 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



/■ 



DESCRIPTION OF A NEW GENUS AND SPECIES O 



BIVALVE FROM THE CORONADO ISLANDS, /^ 

 LOWER CALIFORNIA. ^ 



BY WILLIAM H. I) ALL.* 



During a collecting trip made from San Diego to tiie Coronado 

 Islands by Dr. Fred Baker and Miss J. M. Cooke quite a number 

 of minute sbells were obtained, which were submitted to me for 

 examination. Among them is a small bivalve, with an internal 

 ligament, which can not be referred to any recorded genus. 



Bernardina gen. iiov. 



Shell small, of the general form of Rochefortia, concentrically scnlptnrcil 

 externally, with a conspicuous prodissoconch, which is elevated in the 

 center and at the margins and between these points somewhat excavated ; 

 pallial line entire; hinge with the posterior dorsal margin of the right 

 valve fitting into a shallow groove in the margin of the opposite valve; 

 anteriorly with a strong left lateral fitting between two prominent flexu- 

 ous right anterior laterals; two right and three left cardinals with the 

 resilium posterior to them all. Hinge formula, exclusive of laterals, 

 L. rlO lOl 

 R. rOlOlO ■ 



The type is B. bakeri sp. nov. The genus is named in honor of the late 

 F. Bernard, of Paris, to whom we owe so much of our knowledge of tjie 

 developmental history of the bivalve hinge. 



Bernardina bakeri sp. nov. 



Shell small, short-ovate, white, with sculpture of fine regular concentric 

 grooves with wider interspaces ; moderately compressed ; umbones mod- 

 erately elevated, capped by the prodi.ssoconchs ; internal margins smooth, 

 the posterior adductor scar larger; hinge as de.scribed under the genus, 

 with no external ligament; texture of the shell porcellanou.'^ and rather 

 solid. Length, 2.8; height, l.ii; diameter, 1.0 mm.; the vertical of the 

 beaks behind the middle of the shell about one-ninth the total length. 

 * By permission of the Director of" the U.S. Nat. Museum. 



4C— Proc. Biol. Soc. Wash.. Vol. XXIII, 1910. (171 ) 



