TRANSACTIONS OF WAGNER 



■^"^ TERTIARY FAUNA OF FLORIDA 



Section Plectosolen Conrad, 1867. P. protextus Conrad. 

 Like Solena, with a furrow extending ventrally from the beaks. 



Genus Leptosolen Conrad (Am. Journ. Conch., iii., p. 15, 1867). Type Sili- 



quaria biplicata Conr., Journ. Acad. Nat. Sci., 2d Ser., iii., p. 324, pi. 34, 



fig. 17 (bad), 1858. Middle and Upper Cretaceous. 



Shell like a small, thin Solena, but with a strong clavicular rib directed 



vertically from the beaks towards the ventral margin; the proximal portion 



of this rib in the type species is united with the hinge margin behind by a 



wing, between which and the valve is a deep recess. This genus has shell 



characters nearly intermediate between Solen and Siliqna. The nymphs are 



long and the pallial sinus very shallow. 



Genus Ensis Schumacher, 1817. Type 6". magtms Schumacher. 



Like Solen, but with one right and two left vertical cardinals, and in each 

 valve a posterior horizontal tooth; the valves usually more or less curved. 



Genus Siliqna Megerle, 181 1. Type 5". radiatiis Linne. 



Shell ovate, flattened, straight, with a rib or clavicle ventrally directed; 

 hinge like Ensis, but more feeble. 



Genus Ctiltellus Schumacher, 1817. Type ^. lacteiis Spengler. 



Shell more elongate and often arcuate, the beaks more anterior, the clavicle 

 absent. 



Genus Soleciirtus (Blainville), 1824. Type Solen leguuien Linne. 



Shell more soleniform, ends rounded, beaks subanterior ; a short clavicle 

 below the beaks and another, less evident, passing obliquely forward; pallial 

 sinus well marked ; surface polished. 



Subgenus Pharella Gray, 1854. Type Solen javanicus Lamarck. 



Beaks central ; teeth small, slender ; surface rude ; clavicle absent. 



? Genus Tanysiphon Benson, 1858. Type T. rivalis Benson. 



Shell resembling Pharella, but short, the anterior end shorter, ligament 

 external, with a shorter broad internal resilium set on a short projecting 

 nymph recalling that of Sphenia; pallial sinus deep, siphons long, with a 

 tunic, but retractile; valves very slightly unequal.* 



* This fresh-water shell was very naturally referred to the vicinity of Mya, but the 

 teeth, when present, agree with those of Pharella, and I think it merely a somewhat 

 peculiarly specialized solenoid. 



