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577 



TERTIARY FAUNA OF FLORIDA ^ ' 



third sculpture of moderately elevated concentric lamellae separated by wider 

 radially grooved interspaces ; these lamellae break off abruptly anteriorly, and 

 posteriorly become gradually obsolete in front of the middle of the shell ; they 

 are strongest in front and near the margin ; lunular area lanceolate, large, 

 not impressed, marked by the cessation of the lamellse; escutcheon roundly 

 cordate, impressed; the margins pouting in the middle; there is no circum- 

 scribing line ; beaks turgid, recurved ; interior brilliantly pearly, the basal 

 margin strongly crenulate, the muscular impressions feeble ; base arcuate, 

 ends roynded ; chondrophore narrow, not prominent, anteriorly directed ; 

 the anterior line of teeth long, slightly arched, the posterior meeting it at 

 nearly a right angle, short, straight ; anterior teeth about twenty, posterior six 

 or seven. Lon. of shell 6, alt. 4.5, diam. 3.75 mm. 



This is a very remarkable species which cannot be confounded with any 

 other recent or fossil in the United States. 



Other Tertiary species of Nuciila known in North America and the 

 Antillean region are as follows: From the Eocene: N. ovttla Lea, Midway and 

 Claibornian ; N. viediavia Harris, Midway ; N. magnifica Conr. (+ N. Scdg- 

 wickii Lea), and N. nionroensis Aldr., from the Claibornian ; N. mcridionalis 

 Mey. and Aldr., and N. spheniopsis Conr., from the Jacksonian ; from the 

 Oligocene : N. vicksburgensis Conr. ; from the Miocene : N. diapliana and N. 

 dolabella H. C. Lea, and N. ciineiformis Conr, (1848, Astoria), not of Sowerby ; 

 from the Pliocene : N. cxigua Sby. (San Diego, California, Well), N. baccata 

 Guppy, N. cremdata Hinds (+ N. vieta Guppy and N. temusadpta Gabb), 

 and N. limonensis Gabb ; N. expansa Rve. is reported from the Pleistocene 

 of Hudson Bay, also with iV. temns Mtg., its variety inflata, and N. antiqita 

 Morch, from the Leda clays of the northeastern United States and Canada. 



It is not necessary to mention here the species described as Njicula and 

 since referred to Yoldia or Lcda, which will be found under those genera 

 respectively, but I may note that N. carinifera Lea is the young of IJviopsis 

 cuneus Conr., N. aqinlatera H. C. Lea is a CreneUa, and N. pectiincidaris Lea 

 should be referred to Trinacria. 



Family LEDID^. 



Genus LEDA Schumacher. 



This genus is the Nucidana of Adams, Meek, and others, but not of 

 Link. It has been divided by authors into a multitude of sections, subgenera. 



