32 PLEIOCENE FOSSILS. 



ORTHOCONCLLE.— D'Obb. 



INTEGROPALALiE.— D'Orb. 

 DIMYARIA.— Lam. 



Fam. MYTILID^E. 



MYTILUS.— Lin. 

 MYTILUS INCRASSATUS.— Con. 



Plate XIV., Figs. 1 and 2. 



Mytilus incrassatus, Con., Am. Jour. Sci., Vol. LXL, p. 247, Foss. Ter. For., p. 74, pi. 42, fig. 4. 



M. testa crassa, inflata, arcnata, Icevigata, concentrice lamellosa / lateri buccali sub-arcuato, 

 acuminato ; lateri anali dilato, rotundato ; umbonibus acutis. 



Description. Shell thick, inflated, smooth, with concentric lamellar lines of growth ; 

 buccal margin somewhat arched near the umbones, accuminate ; anal margin round, some- 

 what dilated ; umbones acute. 



This species is remarkable for the thickness of the shell, particularly towards the hinge, 

 and, in this respect, approaches the genus Myoconcha. It is found in North Carolina as 

 well as in South Carolina, but is rare in the latter State. 



Plate XIV., Fig. 1. Exterior of fossil, natural size. 

 " 2. Interior of the same. ' 



Locality. Darlington District and Waccamaw. 



Museum, College of Charleston. 



