TRANSACTIONS OF WAGNER 

 884 



TERTIARY FAUNA OF FLORIDA 



accessory posterior lamella ; laterals very short and feeble, the posterior one 

 obsolete or even absent. Right cardinal with the arms not coalescent above, 

 the anterior arm adjacent to or superposed upon the ventral lamina ; dorsal 

 lamina; and the posterior ventral lamina frequently absent or obsolete ; hinge- 

 plate strong, narrow, and flattish. 



This group is not represented in America, but has representatives in 

 Europe, the China Seas, and part of the Inclo-Pacific region. Species described 

 as Liitraria, from American beds (such as Traskii and transutontana Conrad), 

 belong to other genera. 



Section Guiiioiiuicti-a C. Mayer, 1867. 

 Type Littrariii i>np<ir Deshayes, 1854. Australia. 



Shell having much the form of Tagdits ; dorsal areas strongly plicate 

 above an obscure ray on each side radiating from the beak, the space between 

 the rays ventrally smooth or concentrically striate ; form subquadrangular. 



I know this form only from Reeve's figure, which does not show the 

 hinge, of which Deshayes says the cardinal tooth is prominent and the poste- 

 rior lateral short and lamelliform. The pallial sinus is extremely deep. A 

 single valve from Moreton Bay seems t6 be all that is recorded of this pecu- 

 liar species. 



Section Littrofiliora Dall, 1894. 

 Type Liitraria loiiiplanata C.melin (= planata Chcmn. + costata Tryon). 



Shell inequilateral, ovate, thin, compressed, concentrically waved or 

 plicate; dorsal areas not differentiated; beaks anterior, adjacent; pallial sinus 

 very deep ; gapes large ; left cardinal with the anterior arm adjacent to the 

 rudimental lateral, prominent, wide, the posterior arm walling the pit, without 

 an accessory lamella ; posterior lateral small but distinct ; right cardinal wide, 

 the lamella; not coalescent above, the anterior arm closely apprcsscd to the 

 dorsal shell-margin at the root of the ventral lamina;, posterior arm walling 

 and even overshadowing the pit; posterior ventral lamina developed; dorsal 

 lamina; absent ; posterior sinus in both valves roofed at the apex ; hinge- 

 plate long, somewhat excavated, otherwise as in Liitraria s. s. 



The rare and beautiful species which serves as type for this section bears 

 somewhat such a relation to the ordinary Lutrarias as Raeta docs to Mactrclla. 

 It is poorly figured by Chemnitz, but not referred to by Reeve, in the Iconica. 

 Chemnitz refers it to the Nicobar Islands, and the specimens in the National 



