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TERTIARY FAUNA OF FLORIDA 



mnnnsen. The fundamental feature of Mesodesma, indicated in the name, 

 was regarded as the presence of the cartilage between the hinge-teeth as 

 opposed to its situation behind them in the Crassatella of authors. The 

 difference is apparent and not real, being due to the obsolescence of the 

 posterior laterals in Crassatella, but it seems to have impressed forcibly the 

 writers anterior to Deshayes. 



Gray in the Synopsis of the Contents of the British Museum as early as 

 1840 printed a list of names without diagnosis or types, many of which he 

 afterwards introduced into nomenclature. In 1847, in his list of genera (P. Z. 

 S., pp. 129-219), he seems to have included under Paphia the Mesodesma of 

 Deshayes, to which he does not give an independent standing. He mentions 

 as a synonyme, under number 572, Paphia, "Mesodesma, sp. Desh., 1835, Mya 

 n<>i>u i :~elandi(C ;" and cites as a distinct genus 573," Anapa Gray," with Ery- 

 cina Petitiana Recluz as the type. Ei~i'ilia Turton is also included in the 

 family. The next publication by Gray on this subject was his important 

 summary of 1853 (Ann. Nat. Hist, p. 44) in which the " Paphiadce" are 

 divided, by the presence or absence of a pallial sinus, into two groups. In 

 the first, with " a siphonal inflection," are put Mesodesma Desh., with M. novee- 

 zelandice as type ; Taria n. g., with T. Stokesii n. s. as type ; Donacilla Lam., 

 with D. cornea as type; Paphia Lam., with P. glabrata and vcntricosa ; and 

 Ccronia, with C. denticnlata. 



In the group without a sinus arc included Anapa Gray (1842 and 1847) 

 with an entirely different type from that of 1847, namely A. Smit/iii of Tas- 

 mania ; and Davila Gray, n. g., based on D. polita. 



The above arrangement is good, but the nomenclature is very faulty, as 

 will shortly appear. 



It should be mentioned that in the synonymy of Mesodesma no-.: 

 /audits in a catalogue of New Zealand shells, published in Dieffenbach's New 

 Zealand, 1843, Gray had noted that Leach had used the name Macluena for 

 that species in some of his manuscripts, doubtless in allusion to its solen-like 

 form. In the same year d'Orbigny would adopt Donacilla in place of Meso- 

 desma, a course which is impracticable, because Donacille was never Latinized, 

 described, or typified in a sufficient manner by its author. It would have 

 been better, doubtless, if Deshayes had adopted and established this name 

 instead of proposing a new one, but he was quite within his rights in doing 

 what he did. 



The Adams brothers, Woodward, and others followed Gray in essentials, 



