TRANSACTIONS OF WAGNER 

 59$ 



TERTIARY FAUNA OF FLORIDA 



Range: Paris Eocene; Red and Coralline Crags of Britain; Caloosa- 

 hatchie beds, Florida ; Pliocene of Reggio, Italy ; recent, Straits of Florida, 

 in two hundred and five fathoms. 



This very remarkable little genus combines characters which recall 

 .\iii-iila, Lii/nipsis, Tiiidaria, and other genera, with features peculiar to itself. 

 The history of the genus is quite complicated. 



In 1840 Searles Wood described his genus Plciirodon, as above cited, for 

 P. ovalis of the British Crag, at the same time querying the specific identity 

 of his type with a shell described by Deshayes in 1824 under the name of 

 Niicula iniliaris, from the Paris Basin Eocene. They were not specifically 

 identical, though Wood in 1850 concluded that they were, and therefore 

 enumerated his Crag species under the specific name of iniliaris among his 

 Crag bivalves. But since there was a genus Pieufodonie already existing, he 

 concluded (erroneously, in my opinion) that Plcurodon was preoccupied in 

 zoology, and substituted for it the generic name of Nucinella. Meanwhile 

 d'Orbigny had observed the peculiarities of Deshayes's species, and proposed 

 in 1843 ^0 make it the type of a genus Nuciilina, being apparently ignorant 

 of Wood's Pleitrodon. The word Nuciilina was used by Agassiz in 1847 to 

 include the Nitculidic in a family sense, and about 1850 Filippi, in a rare 

 brochure, used the name Nuciilina for a Cytlicrc or allied entomostracan. The 

 uncertainty of date common to many of d'Orbigny's works led to doubts as 

 to which was the prior use of the name Nucidina in a generic sense. Lastly, 

 in 1860 Arthur Adams named an allied recent shell from Japan Huxlcyia, 

 which, being preoccupied in sponges, he replaced by Cyrilla in the same year. 

 In 1870 a recent species of Pleitrodon was found by Dr. J. G. Cooper while 

 dredging among the islands off Santa Barbara, California. At that time I 

 investigated the relations of these minute forms and had some correspondence 

 about them with Dr. P. P. Carpenter and the brothers Adams. But in the 

 absence of specimens for comparison, and doubting the minute accuracy of 

 the published figures, my notes remained unpublished. In 1886 Dr. W. IT. 

 Rush dredged a single valve of a new species of Plcurodon in the Straits of 

 Florida, and I discovered still another in the Pliocene marls of the Caloosa- 

 hatchie River, Florida. With a series of the Crag shells, specimens of the 

 species described by Deshayes, and of those from Japan and California, I find 

 myself at last in a position to review the group. In 1870 I was informed by 

 Mr. Arthur Adams that his second species of Cyrilla (C. dccussala) was a 

 young Limopsis, which eliminates that form from the discussion. In 1885 



