i6o Bulletin 39 332 



appears in the I^ower Miocene and has continued into the re- 

 cent fauna. 



Gatun Stage: Gatun {Broiuji and Pilsbry). 



Genus XENOPHORA Fischer de Waldheini 



Xenophora conchyliophora Eom 



Trochus conchyliophonis Born, 1778, Mus. Caes. Ind., p. 333. 

 TrocJius aggliitinans Lamarck, Aiiim. sans Vert., vol. 7, p. 14. 

 Phonis aggliitinans Gabb, 1873, Trans. Amer. Phil. vSoc, vol. 15, 

 p. 241. 



Xenophoim conchyliophora Dall, 1892, Trans. Wagner Free Inst. Sci., 



vol. 3, pt. 2, pp. 360-362. 

 Xenophora conchyliophora, Manry, 1917, Bull. Amer. Pal. vol. 5, p. 



297. 



One immature shell was collected from the upper Gatun 

 beds of Old Man Sam Creek. It is one of the few species which 

 has continued pratically unchanged from Upper Cretaceous times 

 to the recent. It is rare as a recent shell along the northern 

 Panama and Costa Rican coast. Gatun Stage. 



Genus PHAS8ANELLA Lamarck 

 Phasianella moSlis, n. sp. 



Shell small, solid, ovate with a short, blunt spire and a 

 small narrow umbilicus; whorls about 4, somewhat convex; su- 

 ture distinct; surface smooth and usually showing no features; 

 in some cases, color markings are preserved as brown, wavy 

 blotches of fiammules and with very faint suggestions of fine re- 

 volving lines which are so common on recent small Phasia7ieUa. 

 Height 3.25, diameter 2.75, aperture 1.50 mm. 



The Phasianella punctata Gabb from the Miocene of Santo 

 Domingo, has a longer spire and different color markings. It is 

 much more like the recent P. affinis than the Costa Rican mollis. 

 P. mollis is related to P. umbilicata d'Orbigny but differs in its 

 sculpture. 



