Costa Rica Miocknk — Olsson 



57 



Turrlcula tawrina, n. sp. Plate 5, figure 3 



Shell small, slender and fusiform; miicleiis of nearly two 

 smooth, convex whorls; post-nuclear whorls about seven; su- 

 tures appressed and bordered by a spiral cord; fasciole about 

 one-half the width of the spire- whorls, smooth; the sculpture of 

 the whorls is spiral, axial ribs lacking; on the spire- whorls there 

 are four raised spiral cords with the flattened interspaces about 

 three times the width of the spirals themselves; on the last whorl 

 and anterior canal, there are 18 or 19 spirals; anterior canal, 

 long, slender and strongly twisted or curved; outer lip simple; 

 anal sinus as indicated by the growth lines is wide, moderate- 

 ly deep and occupies the middle of the fasciole. 



Length 25, diameter 8, last whorl 16 mm. 



This is a small and delicate species, characterized by its 

 slender, fusiform outlines and lack of an axial sculpture. The 

 spirals are narrow, raised cords, rather widely spaced. The 

 single specimen was collected at Bocas del Toro. 



Gatun Stage: Bocas del Toro, Panama. 

 Turricula Terryi, n. sp. Plate 5, figure 4 



Shell small, slender and fusiform, with a long, evenly taper- 

 ing spire and slender, twisted anterior canal; nucleus of two, 

 smooth, small whorls, followed by 8 sculptured post-nuclear; su- 

 ture appressed, bordered by a low, but wide, spiral cord; upper 

 half or more of each spire-whorl, flat or slightly concave and 

 forms the fasciole; fasciole nearly smooth or sculptured with 

 few, low, faint spirals; early spire-whorls strongly sculptured 

 w^ith 12 or 13 axial ribs which are most heavy on the periphery 

 of each whorl; these ribs become progressivelj^ weaker and on the 

 last whorl are only feebly developed on the shoulder or periph- 

 ery; spiral sculpture persistant but weak, consisting on the spire- 

 whorls of 4 cords on the lower half, alternating with much weak- 

 er spirals; the fasciole as already noted is nearly smooth, or very 

 weakly spiralled; on the last whorl, there are 20 spirals, includ- 



