TRANSACTIONS OF WAGNER 

 1 124 



TERTIARY FAUNA OF FLORIDA 



posterior lamella in either valve; adductor scars as in Solecardia; exterior 

 concentrically or radially striate ; form variable but resembling Scintilla and 

 approaching Fulcrella. Type Sciiifilla Cossmanni Dall, Miocene of Virginia. 



This group is intermediate between Fulcrella, Sportella, and Scintilla, but 

 most nearly related to the latter. It is often difficult to say whether one of 

 the smaller more inequilateral forms is a Montacuta or should be placed here. 

 Nearly all the species I have been able to examine have a single tooth in each 

 valve and no trace of a posterior lamella. The difference in form between 

 the right and the left tooth is very marked. As far as I can judge from 

 figures all the species from the Parisian Eocene referred by M. Cossmann to 

 Scintilla will find a place in this group, together with all the American Tertiary 

 forms. The obsolete amphidetic external ligament of the recent Scintillas 

 leaves little or no trace of its existence on the shell ; I believe it likely that 

 S paniorinus had a similar ligament, but this must remain in doubt for most of 

 the species. In allotting the species of these puzzling shells to a genus I have 

 placed those with a coarse hinge, double anterior cardinals, and which show 

 a distinct scar of the external ligament in Sportella; those very inequilateral, 

 with delicate hinge and no external ligament, in Moiifaciita,'^ and, in Scintilla, 

 those with the hinge above described, v/ith nearly equilateral shells, no ex- 

 ternal ligament scar, and frequently with radial sculpture of fine, sharp striae. 



Scintilla recondita Fischer would probably belong in Spaniorinus. In spite 

 of Jeffreys's opinion, I do not think it identical with the Eocene S. Caillati Desh. 

 But specimens from Monte Mario, distributed under Deshayes's name by 

 Rigacci, belong to Fischer's species. 

 Subgenus Scintillorbis Dall. ' 



Shell compressed, orbicular, extremely thin, with radial and concentric 

 sculpture, an obsolete external Hgament, a stronger internal resilium ; dental 

 formula ~^. Type 5. crispata Fischer, 1872. 



This is entirely unlike the typical Scintilla, and, except for the hinge, re- 

 sembles an orbicular Lepton. It does not appear that any of the so-called 

 Scintillas of Europe or America, recent or fossil, closely resemble .the tropical 

 and chiefly Oriental typical forms. 



"Sportella corbnlina Deshayes, from his figure, would be placed in this paper under 

 Montacuta. 



