TRANSACTIONS OF WAGNER 

 1050 



TERTIARY FAUNA OF FLORIDA 



Pliocene marls of the Caloosahatchie River, Florida; Dall. Recent from 

 Cape Cod southward to Rio Janeiro. 



T. Souleyetiana differs from the northern specimens of T. tenta only by 

 the warmer flush of yellow or orange which suffuses the umbonal region of the 

 valves, and perhaps in having a little smoother periostracum. As these dif- 

 ferences are obviously such as are correlated with a more southern habitat, the 

 forms can hardly be separated specifically. M. virginiana Conrad is their 

 Miocene precursor. 



Macoma constricta Bruguire. 



Solen constrictus Brug., Mem. Soc. Hist. Nat., i., p. 126, No. 3, 1799. 

 Psammobia cayennensis Lamarck, An. s. Vert., v., p. 514, 1818. 

 Tellina cayennensis Deshayes, An. s. Vert., ed. ii., vi., p. 177, 1835 ; Hanley, Thes. Conch., 



p. 312, pi. 62. fig. 190, 1846. 



Tellina constricta Philippi, Abb. und Beschr., i., p. 9, pi. I, fig. 5, 1843. 

 Tellina lateralis Say, Journ. Acad. Nat. Sci. Phila., v., p. 218, 1827. 

 Tellina cayennensis Holmes, P.-P1. Fos. S. Car., p. 47, pi. 8, fig. 4, 1859. 

 Macoma constricta Dall, Bull. U. S. Nat. Mus., No. 37, p. 60, 1889. 



Pliocene of the Caloosahatchie River, Florida, Dall; Pleistocene of South 

 Carolina, Holmes ; recent from the coast of New Jersey south to Brazil. 



This species appears to be rare in the Pliocene, as only a single valve was 

 obtained, but it is unmistakably conspecific with the recent shell. 



Macoma laxa n. sp. 

 PLATE 47, FIGURE 14. 



Pliocene marl of the Caloosahatchie River, Florida ; Dall. 



Shell thin, nearly equilateral, elongate, moderately convex, with incon- 

 spicuous beaks ; anterior end a little longer, higher, and rounded, posterior 

 attenuated, compressed, pointed ; not obviously flexuous ; surface sculptured 

 only with rather rude, somewhat irregular incremental lines ; posterior termina- 

 tion near the base, posterior dorsal margin moderately arched ; hinge normal, 

 with minute feeble teeth; pallial sinus discrepant in the two valves, elongate 

 but not quite reaching the anterior adductor, in the right valve slightly an- 

 gular above under the umbo, in the left valve only slightly sinuous there, in 

 both wholly confluent below with the pallial line ; interior of the valves faintly 

 radially striated, especially near the base. Lon. 23, alt. 13, diam. 6 mm. 



This species has a peculiar outline and does not closely approach any of the 

 other species of Macoma from the region. 



