TRANSACTIONS OF WAGNER 

 1502 



TERTIARY FAUNA OF FLORIDA 



of nomenclature as above set forth. It is always disagreeable to use a familiar 

 name in an unfamiliar sense, but, luckily, the use of Sph&rium for the Lamarck- 

 ian Cyclas is now universal, and the unwarranted resuscitation of the non- 

 Linnean Cyclas of Klein by Morch in 1853 has found few advocates, so the 

 students of the present generation will be less annoyed by the present neces- 

 sary change in the use of this name. 



Cyclas islandica is only known in the fossil state in America from the raised 

 beaches of the boreal region of late Pleistocene age, but allied species appear 

 in the Crag of Iceland. The recent shell extends in cold water from the Arctic 

 Atlantic to Cape Hatteras, North Carolina, in six to two hundred and sixty- 

 four fathoms. It is not circumboreal. 



Genus ETJLOXA Conrad. 



Euloxa Conrad, Proc. Acad. Nat. Sci. Phila., xiv., pp. 578, 585, 1863 ; xxiv., p. 52, pi. i., 

 fig- 5, 1872; Meek, Checkl. Inv. Fos. Miocene, p. 7, 1864. 



Shell subovate, truncate behind, with a wide, shallow sulcus extending from 

 the beaks to the sulcation, bounded on each side by a rather obtuse keel ; sur- 

 face concentrically sculptured ; dorsal areas feebly impressed but without de- 

 fined lunule or escutcheon ; inner margins smooth, pallial line entire ; hinge 

 with three cardinals in the left valve, the middle one largest, the posterior 

 dorsal valve margin bevelled so as to enter a shallow groove in the margin of 

 the opposite valve; right valve with two cardinals, the anterior entire, tri- 

 angular, the posterior elongate and bifid; ligament external, inserted on 

 nymphs. Dental formula L - I - 10101 -. Type Venus latisulcata Conrad. Miocene. 



J r R. o.oioio. J r 



Euloxa latisulcata Conrad. 



Venus latisulcata Conrad, Fos. Medial Tert., p. 40, pi. xx., fig. 6, 1840. 

 Astarte latisulcata Orbigny, Prodrome Pal., iii., p. 112, No. 2089, 1857. 

 Euloxa latisulcata Conrad, Proc. Acad. Nat. Sci. Phila., xiv., pp. 578, 585, 1863; xxiv., 

 p. 52, pi. i., fig. 5, 1872; Meek, Checkl. Inv. Fos. Miocene, p. 7, 1864. 



Miocene of Middlesex County, near Urbana, Virginia ; Conrad. 



This apparently is a rare species, as I have seen only the types in the Phila- 

 delphia Academy's collection, which were courteously loaned me for study. 

 The genus, which has been referred to the Venerida and Astartidoe, is a 

 Cyprinoid, in which the posterior laterals have become obsolete, being clearly 

 defined only in the young or adolescent shell. 



