26 PLEIOCENE FOSSILS. 



JANIKA AFFINIS.— {New Species.) 



Plate VIII., Figs. 5 and 6. 



P. testa subrotunda, tenui ; valva inferior e, convexa cequilaterali, extus laevigata, intus 

 binis radiatim costata ; auriculis sub-cequalibus. 



Description. Shell almost circular, thin ; lower valve convex, equilateral ; smooth on 

 the outside, with radiating undulations or obsolete ribs, striated concentrically ; on the 

 inside rayed with narrow ribs in pairs ; ears nearly equal. The ribs on the inside corres- 

 pond with the intermediate spaces of the obsolete ribs on the outside. The buccal ear is 

 slightly expanded and crossed by undulating striae, and with an obtuse ridge terminating 

 in the sinus. Although but a single lower valve has been found, the wide channel and 

 corresponding ridge, on the outside of the buccal ear, are sufficient to refer it to the genus 

 Janira. The thinness of the shell and interior costas give it some resemblance to P. Mor- 

 toni, but it is separated from it by the sinus for the byssus, and greater convexity of the 

 shell. 



It also resembles J. Ziczac, of the coast of Florida ; the latter, however, has the lower 

 valve more convex, the umbones more prominent, and the flattened external ribs better 

 defined, and marked by an impressed line towards the pallial margin. 



The genus Janira commenced its existence in the ocean of the cretaceous period, is 

 found in the tertiary, and is still an inhabitant of the seas of warm and temperate climates. 

 Both the tertiary and recent species are of greater size than those of the cretaceous. 



Plate TIE, Fig. 5. Under side of lower valve, natural size. 

 " 6. Interior of same. 



Locality. Smith's, Goose Creek. 



Museum, College of Charleston, S. C. 



