292 ■ . NEW YORK STATE MUSEUM 



prominent, projecting and clear-cut revolving keels on penultimate 

 whorl, the uppermost of which is the weaker and forms the outer 

 edge of a flat revolving shelf which is depressed at an angle of 

 about 115° from the vertical axis. The edge of this keel is narrow 

 and rather vertical. Just under it a second shelf commences, having 

 about the same width and angle as the first; it is slightly concave 

 and is limited by the second and stronger keel. Under this is a 

 wider, more strongly concave space with its lower border sloping 

 down at an angle of about 45° to the vertical; the limiting keel to 

 this revolving groove is the strongest and most extended of all. 

 The edge of the shell is now cut strongly back, beginning at an 

 angle of about 90° with last surface and curving down to a very 

 fine keel immediately above the suture or reaching the suture itself. 

 The suture thus comes to lie in the widest and deepest revolving 

 channel of the shell. There are five or six fainter revolving keels 

 on the base but the shell is not depressed between them ; the three 

 next to the columella are the nearest together. The lip is broken 

 but appears to have been well rounded and to have been slightly 

 extended over the columella at the base of the outer lip so as to 

 leave a very narrow and slitlike cavity appearing like a nearly cov- 

 ered umbilicus. The revolving keels do not begin to show till the 

 latter part of the second whorl. Very fine and faint transverse 

 striae, about 10 to the .millimeter, cross the later whorls, and the 

 edges of the keels are slightly roughened or finely nodular. 

 Collected by Mr Percy E. Raymond. 



Genus strap arollina Billings 

 Straparollina harpa sp. nov. 



Plate 5, figures 4, 5 



Shell very small, turbinate, spire low, hight 2.5mm, width about 

 4mm, apical angle about 125°. Whorls three, well rounded, rapidly 

 enlarging, crossed by fine raised, laminate ridges, vertical to the 

 surface and about .2mm apart. Umbilicus deep, about one ninth the 

 width of the shell, the lip at the notch extended and partly reflected 

 over it. 



