TRANSACTIONS OF WAGNER 

 980 



TERTIARY FAUNA OF FLORIDA 



It is probable that to the rarity of this very remarkable shell is due the 

 little attention which it has attracted, and the incongruous species which have 

 been associated with it. It has the form of Tagchts divistts, with the color, 

 texture, solidity, and strong internal marginal grooving of Donax. The sur- 

 face is smooth, with the caducous periostracum and suppressed radial sculp- 

 ture of such species as Donax variabilis. The nymphs are slender and short, 

 the pallial sinus short, rounded in front, and partially free below. There are 

 two cardinals on the right and three on the left valve, the posterior tooth in 

 the latter being more or less merged with the nymph. It is perhaps nearest 

 in the family to some of the species of Psammotcea. It occurs recent and in 

 the quaternary of the west American coast near Mazatlan, Mexico. 



Genus HETERODONAX Morch. 



Heterodonax Morch, Yoldi Cat., ii., p. 15, 1853. 



Arcopagia Orbigny, 1853, not of Brown, 1827. Type H. bimaculata L. 



This is one of the few species which are abundant unmodified on both sides 

 of the isthmus connecting the two Americas, extending on the Atlantic side 

 from Fernandina, Florida, to Brazil, and on the Pacific from Southern Cali- 

 fornia to Panama. It is found in the Pleistocene of south Florida, the An- 

 tilles, and both shores of Central America and Mexico. The typical species 

 was described by Conrad from San Diego as Psainmobia pacifica, and occurs 

 in the Pleistocene of Southern California. 



Genus ASAPHIS Modeer. 

 Asaphis Modeer, K. vetensk. Acad. nya Handl., xiv., pp. 176, 182, 1793. Type Venus 



defiorata L. 



Capsa (sp.) Bruguiere, Enc. Meth., 1792. 

 Capsa Lamarck, Syst. An. s. Vert, p. 125, 1801 ; not of Prodrome, p. 84, 1799, or An. s. 



Vert., v., p. 553, 1818. 



Corbula (sp.) Bolten, 1798; not of Bruguiere, 1792. 

 Capsula Schumacher, Essai, pp. 130-31, 1817. 

 Psammocola (pars) Blainville, Man. Conch., p. 567, 1825. 

 Sanguinolaria Deshayes, 1835; not Lamarck, 1799. 

 Pleiorhytis Conrad, Proc. Acad. Nat. Sci. Phila. for 1862, p. 286, 1863. 

 Pliorytis Conrad, ibid., p. 576. 

 Heteroglypta Martens, Meeresf. von Mauritius, p. 331, 1880 (ex parts). 



This group, which is rather closely allied to the typical Psammotaa, may be 

 divided as follows: 



