TRANSACTIONS OF WAGNER 

 I 342 



TERTIARY FAUNA OF FLORIDA 



The Linnean species, among several closely similar forms now known, cannot 

 be positively identified, but, according to Hanley, is probably the L. ovum 

 Reeve, a Red Sea species. The genus, however, is unmistakable, and was sub- 

 sequently named Anodontia by Link (1807). 



In 1791 Poli recognized the chief anatomical peculiarities of a Mediter- 

 ranean species, and Loripcs, one of several names he applied to it, was intro- 

 duced into binomial nomenclature by Oken in 181 5, and adopted by Cuvier two 

 years later for the Tellina lactea (Poli) Gmelin (non Linneeus), which has 

 many synonyms. 



In 1817 Schumacher named several Lucinoid forms, though several of the 

 names were already in use, and that which he adopted as typical Lucina is not 

 the original Lucina of Lamarck. 



In 1822 Turton proposed Myrtcsa for the Venus spinifera of Montagu, and 

 in 1825 Blainville gave the name of Phacoides to a group typified by Lucina 

 jamaicensis of Lamarck, the Tellina pectinata of Gmelin. Subsequent divisions 

 will be treated under their particular heads, the above synopsis accounting for 

 the nomenclature of the chief groups in their historical sequence. 



The dental formula for the Lucinidce, in its fullest development, appears to 

 be single right and double left laterals on each side of the beaks, while the 

 cardinals are ^- '°= -°. The inner pair, if any, are those which are grooved or 

 bifurcate, though they are often entire, while the outer pair show no bifurca- 

 tion. The anterior right cardinal is frequently absent or represented only by 

 a rudiment, and a single right cardinal is characteristic of the genus Myrtcea. 

 In other groups, unless well developed, the dwarfed cardinal may be indiflfer- 

 ently present or absent in difl^erent stages of the same individual or different 

 individuals of the same species. It is almost invariably absent when the lunular 

 impression is exceptionally deep, as often occurs, leaving no space for the 

 anterior tooth to develop. 



The teeth are very subject to reduction by obsolescence, sometimes the lat- 

 erals, sometimes the cardinals, and sometimes both, becoming gradually obso- 

 lete in the adult shell. It often happens that the young shells of the same 

 species will show a relatively well-developed dentition when the adult has hardly 

 a trace of the teeth. The cardinals in species which have a deeply impressed 

 lunule.seem to be affected injuriously by the invagination of the margin adja- 

 cent to them. The laterals as a rule, as in other groups, are less constant in 

 their development than the cardinals. The duplication of the lateral laminae 

 to hold the single lamina of the opposite valve is, in all the cases I have studied, 

 developed in the left valve, though Bernard ascribes it to the right valve, per- 



