i577 Costa Rica Miocene — Oi^sson 105 



Similiar in general form and in the number of its ribs to the 

 F. miccosmius from Bocas, this species differs in its smaller, 

 heavier shell, and in the greater coarseness of its sculpture. The 

 spirals are heavier and primary in character throughout and the 

 ribs are more knobbed and sharp on their crests. From the Do- 

 minican F. Henekeni Sowerby, it differs in being much more 

 slender and with fewer, persistent ribs. 



Gatun Stage: Coll. Home Walk Creek. 



Genus FASC SOLARIA Lamarck 



Fasciolaria Gorgasiana Brown and Pilsbry Plate 8, figure 9 



Fasciolaria gorgasiana Brown and Pilsbry, 19 12, Proc. Acad. Nat. 

 Sci. Philia., vol. 64, p. 506, pi. 22, fig. 5. 



This large Fasciolaria is fairly abundant in the Gatun beds 

 of the Canal Zone and is recognized by its shouldered whorls and 

 and strong knob-like ribs. The figured specimen is a large shell 

 from the Gatun of Rio Betey, Costa Rica. 

 Gatu7i Stage: Gatun, C. Z. 



Water Cay. 

 Rio Betey. 



Fasciolaria tulipa Linnseus, variety Plate 13, figure 4 



Murex tulipa Ivinnaeus, 1758, Syst. Nat.,ed. 10, p. 754. 

 Fasciolaria tulipa Gabb, 1881, Journ. Acad. Nat. Sci. Phila., vol. 8, 

 2nd series, p. 354. 



Fasciolaria tulipa Dall, 1890, Trans. Wagner Free Inst. Sci., vol. 3, 

 pt. I, p. loi, pi. 7 fig. II 



The Tulip shell is the common, recent Fasciolaria, in the 

 Caribbean area, and it is distinguished from its more northern re- 

 lative, the dista7ts, by its darker coloration and sulcated sutural. 

 band. It occurs as fossil in the Pliocene of Florida. 



From the coralline limestones, near Port Limon we collected 

 three young specimens and a portion of the spire of a large in- 

 dividual of Fasciolaria. The young shells show the nucleus and 



