1034 PELEOYPODA. [Eulamellibranfhia. 



Fam. VERTICORDIID^, Wood. 



Animal having the mantle-edges united on the ventral surface, 

 thick, not fringed with papillae ; siphons short, surrounded by a 

 circular fringe of ' papillae ; foot small, distinctly grooved behind, 

 generally not byssiferous ; palps well developed ; gills papillose. 



Marine. 



Shell equivalve or very little inequivalve, cordiform. rounded, 

 oval or trapezoidal, inequilateral ; the anterior end short ; beaks 

 produced, incurved, more or less detached, spiral or subspiral ; in- 

 terior pearly ; hinge asymmetrical, with a tooth in the right valve 

 and a corresponding callosity in the left valve ; ligament in a sub- 

 internal groove, bearing a lithodesma ; adductor-scars distant ; pallial 

 line entire. 



Tertiarv to Recent. 



ti 



Genus 1. VERTICORDIA, Wood, 1844. 



Verticordia (Wood MS.), Sowerby, Min. Conch., vii, 1844, 67, pi. 1139. 

 Type : Cryptodon verticordia, S. Wood + Hippagus cardiiformis, Sowerby. 

 Hippagus, Philippi, 1844; not of Lea, 1833. Cryptodon (sp.), Wood, 

 1840 ; not of Turton, 1822. Iphigenia, Costa, 1850 ; not of Schumacher, 

 1817. Hippella, Morch, 18(51. Verticordia, Seguenza, J. de Conch., 

 viii, 1860, 286 : Fischer, op. cit., 295 : Dall, Bull. Mus. Comp. Zool., tx, 

 1881, 105 ; xii, 1886, 285. 



Shell small, more or less convex, with a deeply impressed lunule, 

 and a large, arched, bridge-like ossicle attached below the beaks to an 

 internal cartilage in each valve ; this ossicle is expanded outward 

 at its posterior end, and in the most typical species is much broader 

 than long ; the right valve has a strong conical tooth behind the in- 

 ternal convexity due to the impressed lunule, and no lateral tooth ; 

 the left valve has the lunular edge produced to fit in front of the car- 

 dinal tooth of the right valve, and has the upper surface of the posterior 

 hinge-margin bevelled away so that that edge may fit under the 

 opposing edge of the right valve ; the cardinal tooth in young speci- 

 mens is grooved axially, but when adult is conical ; the line of the 

 external ligament is continued under the spiral of the beaks. (Dall.) 



Distribution. Atlantic, Antilles, Chinese seas, New Zealand. 

 Australia. 



Fossil in the Tertiary. 



Subgen. 1. HALIRIS, Dall, 1886. 



Haliris, Dall, Bull. Mus. Comp. Zool., xii, 1886, 287. Type: Verticordia 



Fischeriana, Dall. 



Shell globose, ossicle short, squarish ; lunule present, not deep ; 

 right valve with a strong conical cardinal and a long lateral tooth ; 

 left valve with (in the adult) a small but distinct cardinal tooth and a 

 short stout lateral tooth near the umbo ; lunule not produced ; ado- 

 lescent or young shells with the dentition obscure or imperfect. (Dall.) 

 The type is from the Gulf of Mexico, 84 fathoms. 



