TRANSACTIONS OF WAGNER 



TERTIARY FAUNA OF FLORIDA 



alists. Bruguiere placed this species first in his list in 1789. Poli, who did 

 not adopt the Linnean nomenclature but had two genera, one for the shell 

 and one for the soft parts, called it Daphne and Daphneoderina in 1795. In 

 1835 Swainson gave it the name of Byssoarca ; it was included in his section 

 Les fiavicules by Blainville in 1825, though he did not name it Naviaila, as 

 sometimes stated. Cyplioxis Rafinesque, 18 19, was probably intended to 

 cover fossil species of this type, but as no described species were referred to 

 it, it remains unrecognizable; Thyas Gray (Figures of Moll. An., v., p. 24, pi. 

 358, fig. 4, 1857) is another synonyme, but the name was used for another group 

 in 1835; Browne was not a binomial writer, and his Cibota, used by Morch 

 in 1852, also falls into synonymy. Lastly, Arcopkra Heilprin, based on the 

 following species, does not present, when a large series is compared, any con- 

 stant characters which would separate it from the restricted genus Area. 



Before proceeding to describe the species collected it is necessary to 

 review the nomenclature and settle on the characters of the subdivisions to be 

 adopted. This has been a work of considerable labor; the inaccuracy of the 

 diagnostic characters given in the text-books is so astonishing, when they are 

 compared with a series of the species, that one is tempted to believe such 

 diagnoses are written without any reference to specimens or, at best, with only 

 a single specimen for comparison. The examination of over one hundred 

 species of fossils and a majority of the known recent species of Area has en- 

 tirely confirmed the opinion expressed by several authors, that a gradual 

 transition may be traced between the groups which have been described as 

 genera and subgenera with extremely few exceptions. 



Subgenus BARBATIA (Gray) Adams. 

 Batbatia Gray, Synops. Brit. Miis., 1840, p. (?) ; ibid., 1844, p. 81. Type Area barbata 

 L., H. and A. Adams, Gen. Rec. Moll., ii., p. 534, 1858. 



The type form of this group is tolerably regular and seldom deformed, 

 like the typical Arks, from the anfractuosities of its station ; the reticulated 

 sculpture shows few irregularities ; the cardinal area is narrow with numerous 

 grooves for the resilium, which form a series of elongated concentric lozenges 

 on the area ; the shell is not conspicuously truncate or keeled ; the teeth are 

 small and vertical in the middle of the series and towards the end diverge 

 distally and become larger and more distant. In some species these distal 

 teeth are often broken up, like those of CneulUca, but this feature is not con- 

 stant in the species. Several groups or sections are recognizable, though 



