1919.] E. W. Vredenburg : Shells of the family Doliidœ. 157 



linear with forward facing convexity, and is oblique, antecurrent to the posterior 

 suture, retro current to the anterior suture. 



The protoconch is followed by three to three and a half convex spire-whorls, 

 separated by slightly sunken sutures. Their height varies from two-ninths to a 

 little over one-quarter of their width, the maximum thickness coinciding with the 

 anterior margin. The whorls usually exhibit four ribbon-like main ribs, considerably 

 narrower than the intervening spaces which are slightly concave. The most posterior 

 main rib, which is narrower than the others, encircles the circumsutural depression. 

 The most anterior rib coincides with the anterior margin and is frequently more or 

 less overlapped by the posterior edge of the next following whorl. In rare instances, 

 the spire is so much sunken that the posterior edge of each whorl reaches the level 

 of the third primary rib of the preceding whorl. The intervals between the primary 

 ribs may be approximately equal, though usually the most posterior interval is 

 somewhat wider than the remainder. On the first whorl following the protoconch, 

 each interval usually carries three delicate subsidiary spiral threads, namely a median 

 thread of the second order flanked by two threads of the third order. Occasionally 

 one of the threads of the third order may be atrophied or indistinct. On the second 

 whorl, the threads of the third order disappear, leaving only, in each interval, the 

 median thread of the second order which also becomes gradually thinner and indis- 

 tinct with increasing growth. On the third whorl all the threads of the second order 

 may likewise disappear, leaving the intervals perfectly smooth, but there usually 

 subsists a more or less distinct remnant of the line intersecting the most posterior 

 interval, usually reaching even to the body-whorl. A number of extremely fine 

 spiral lines are usually observed on the surface of the main ribs. The extremely fine 

 crowded lines of growth, especially distinct and regular on the first whorl following 

 the protoconch, are practically straight and strongly oblique, antecurrent to the 

 posterior suture, retrocurrent to the anterior suture. 



The large body-whorl constituting the greater part of the shell is always 

 strongly inflated and globose, and may be almost spherical, but is more usually 

 distinctly ovoid. On the right side of the shell its convexity is continued as far as 

 the anterior termination, while on the left side a shallow concavity intervenes 

 between the main basal convexity and the zone of accretions to the very deep 

 dorsal notch, whose outline, on the left side of the shell, viewed dorsally, is steeply 

 oblique anteriorly towards the right and slightly convex. The actual edges of the 

 notch are slightly reflected outward. Ventrally, the steeply winding anterior edge 

 of the terminal zone of accretions is bounded by the foliaceous termination of the 

 columella and columellar margin, with the formation of a narrow umbilicus. Includ- 

 ing the spiral ornaments continued from the spire, and irrespective of the ridge 

 forming the posterior edge of the terminal zone, the body-whorl, in the case of small 

 specimens measuring less than 35 mm. in height, carries twelve primary ribs. In 

 specimens measuring from 35 to 45 mm., the number of primary ribs is usually 

 thirteen. In the majority of specimens ranging from 45 to 100 mm., the number of 

 primary ribs is fourteen, though, occasionally, amounting only to thirteen. At still 



