Costa Rico Miocknk — Olsson 



99 



drical, widest about the upper half; aperture sublinear, with a 

 slightly thickened lip, somewhat contracted in the middle, smooth 

 within; inner lip smooth, or with only a thin wash of callus and 

 with 4, very oblique plications at its extreme anterior end. 

 Length 9.25, diameter 3.25, spire 2.75 mm. 

 A small, slender species of unusual form. Two specimens 

 were collected in Costa Rica, the type from the Banana River, 

 the other from Old Man Sam Creek, near Manzanilla Point. 

 Gatun Stage: Banana River, 



Alo7ig Old Man Sam Creek, one mile south 

 of the beach, C. R. 



Genus VOLUTA lyinnseus 

 Voluta alfaroi Dall Plate 8, figure 2 



Valuta alfaroi 191 2, Smith, Misc. Coll., vol. 59, No. 2, p. 8. 



This fine species described by Dr. Dall, from the Banana 

 River, is a common and very characteristic fossil or the Gatun 

 beds in Costa Rica and Western Panama, but it still remains to 

 be recorded from the Canal Zone. Allied to the recent West 

 Indian V. jnusica Linnaeus it differs most importantly in its 

 much smaller nucleus. 



The shell is heavy and in its typical form the whorls are 

 shouldered and carry about 12 ribs, which may be quite sharp 

 and high on the shoulder angle. The whorls are sometimes 

 smooth, without ribs and a shoulded angle. Spiral threads usu- 

 ally occur on the lower one-quarter of the last whorl and on the 

 canal, but in some cases on the spire- whorls as well. A large 

 specimen from Water Cay m.easures; 



Height 59 mm. diameter 34 mm. 

 Gaiii7i Stage: Water Cay Panama. 



Coll. J, Red Cliff Creek; Old Man Sam Creek, 

 I mile f7^07?i shore; Coll. 2, Quitana Creek; 

 Coviadre Creek; Son si creek; Coll.^, Estrella 

 River ;Ba7iana River; Rio Blanco ;Port Limon. 



