TRANSACTIONS OF WAGNER 

 1 162 



TERTIARY FAUNA OF FLORIDA 



however, in different individuals so much that it is ahnost impossible to sepa- 

 rate a large series without finding a fair proportion of strictly intermediate 

 specimens, and I find the same true of the original R. bidentata, of which I 

 have examined a very large series covering all parts of its geographical range. 



These small shells are very puzzling and require close study to discriminate, 

 but I think no one who had gone carefully over the series in the Jeffreys col- 

 lection would hesitate to pronounce the European and American shells distinct. 

 The former are smaller, more convex, more inequilateral, more quadrate, more 

 elongate, and have smaller dental lamellae than the average American specimens, 

 and I have not found any adult specimens which could be called intermediate. 



The Kellia rubra of Dr. Gould in 1841 was a mixture of two species, one 

 of which was Turtonia luinnta, and the other, which he figured, the present 

 shell, to which Stimpson in 185 1 gave the name here adopted. What Dr. 

 Gould thought were the young and found among the roots of seaweed, as he 

 himself informed me, were the Turtonia. The Rochefortia, when containing 

 the dried remains of the animal, has a ruddy tinge and a pale-brown epidermis, 

 which are lost in the washed valves found on the beach. In Binney's edition 

 of Gould K. planulata is rather badly figured and no scale is given for the 

 magnified illustration. Both the typical form and the variety tenuis occur in 

 the Caloosahatchie marls. The R. striatula V. and B. and the R. Molleri Morch 

 {Montacuta elevata Morch, 1875, i^ot Stimpson, 1851) have also been con- 

 fused by authors with R. planulata, from which both are easily discriminated 

 when the characters are pointed out and carefully studied. Miss Bush states 

 (Science, N. S., x., p. 250, Aug. 25, 1899) that the Lascea planulata of Ver- 

 rill's Checklist of 1870, dredged at Halifax, Nova Scotia, by the United States 

 P'ish Commission, is not Stimpson's species but R. Molleri. 



Genus LAS.^A Leach. 

 Lascea (Leach) Brown, 111. Con. Gt. Brit., ist ed.. pi. 20, figs. 17-18, 1827; 2d ed., p. 93, 



pi. 36, figs. 17-18, 1844; Zool. Textb., p. 451, 1833; Conch. Textb., p. 128, 1833. Type 



Cardium ruhruin Montagu ; Gray, Ann. Mag. N. Hist., xx., p. 272, 1847. 

 Lasea Gray, P. Z. S., 1847, p. 192 ; Moll. Gt. Brit., p. 289, 1852. 

 Autonoe Leach, Moll. Gt. Brit., p. 288, 1852; C. rubrum Mtg. 

 Cycladina Cantraine, Bull. Acad. Brux., ii.. p. 399, 1846. Type Chama poron Adanson 



=: C. Adansonii Cantr. 

 Poronia Recluz, Rev. Zool., p. 166, 1843 {Chama poron Adans.) ; Philippi, Zeitschr. Mai. 



f. 1847, p. 72. 

 Anapa Gray, P. Z. S., 1847, p. 186. Type Erycina petitiana Recluz {—Lascea rubra Mtg.). 



