TRANSACTIONS OF WAGNER 

 982 



TERTIARY FAUNA OF FLORIDA 



The genus Tagclus is distinguished from any of the Solenida; by its long 

 and distinct siphons. In its other characters it approaches closely to Psam- 

 motcea. Adanson in describing his Solen tagal has given it the siphons of a 

 true Solen, which is doubtless erroneous, since if his figure and description were 

 correct the species would belong not only to a distinct species, but to a different 

 family from the American shells, which have usually been specifically united 

 with it on conchological grounds. 



The group to which this genus belongs may include the following divisions, 

 all of which are more closely related to Psammobia than to the Solenidcc, among 

 which they were formerly placed. 



Genus Novaculina Benson, 1830. Type N. gangetica Benson. 



Beaks subanterior; teeth (when fully developed), three in the left and two 

 in the right valve ; the anterior left tooth often obsolete or wanting, the an- 

 terior right tooth bifid ; valves without a median constriction or clavicular 

 internal rib ; pallial sinus short, not reaching the beaks ; posterior adductor 

 scar rounded ; the ventral portion of the pallial sinus distinct from the pallial 

 line below it ; situs in fresh water of Indian rivers. 



Loncosilla Rafinesque, 1820, as pointed out by Stoliczka, was probably 

 founded on a defective specimen of Novaculina, but is unidentifiable. 



Section Clunaculum Dall. Type Solecurtus mollis (Gould MS.) Sow- 

 erby, Conch. Icon., pi. vi., fig. 26, 1874. Coasts of Brazil and 

 Uruguay. 



Beaks subanterior; teeth two in each valve, the posterior left tooth bifid 

 (with in some species an obsolete tooth behind it) ; valves obliquely con- 

 stricted, the constriction reflected by an internal thickened elevation (not a 

 rib or clavicle) ; the pallial sinus not reaching the beaks; posterior adductor 

 scar triangular ; the ventral part of the pallial sinus wholly coalescent with the 

 pallial line ; situs estuarine or marine. 

 Genus Tagelus Gray, 1847. Type Solen gibbus Spengler. West Africa and 



East America. 



Beaks median or subposterior ; teeth two in each valve, simple, pedunculate ; 

 valves without constriction or clavicle, straight; pallial sinus deep, reaching 

 to or beyond the beaks ; posterior adductor scar rounded ; pallial sinus with 

 the ventral part partially coalescent with the pallial line; situs estuarine or 

 marine. 



The shell figured by H. and A. Adams to illustrate Tagelus is a Novaculina, 

 \nd their diagnosis is a mixture of the characters of Novaculina and Tagelus. 



