Bulletin 39 238 



orly by a strong sutural cord; the spiral sculpture consists on 

 the early whorls of 2, later 3 and finel}^ 4 cords on the penulti- 

 mate whorls; the last whorl has 8 spiral cords and 10 others on 

 the canal; the spiral cords are separated by interspaces of slight- 

 ly greater width; the interspaces are finely striated with small 

 spiral threads; the axial sculpture consists of about 9 knot-like 

 ribs over v/hich pass the enlarged spiral cords; the ribs pass over 

 the base of the last whorl to the canal and slightly over the fac- 

 ciole; aperture elliptical with a short, straight canal. 



Height 18, diameter 6, last whorl 9 mm. 



This is a diminutive of Drillia fusiformis of the Miocene of 

 Santo Domingo, the two species having practically the same 

 sculpture. Drillia fusiformis of 11 whorls measures 35 mm in 

 length, while aqiianica of the same number of whorls has a 

 length of onh'- 19 mm. The Maury collection contains a small 

 but quite typical specimen of aquanica from the Rio Gurabo, 

 Santo Domingo. 



Gatun Stage: Water Cay. 



Driilia limoniea, n. sp. Plate 4, figure 15 



In general form like Di^illia consors Sowerby, with a long 

 spire and but slightly shorter anterior canal; whorls about S>^ of 

 which 1Y2. belongs to the small, smooth, blunt nucleus; the 

 post-nuclear whorls are sculptured with ribs and weaker spirals ; 

 on the I St three whorls, the anal fascicle is but slightly differ- 

 entiated; it increases slowly in strength until on the later whorls 

 it has become a concave zone as in consors \ a sutural cord is in- 

 troduced on the 2nd post- nuclear whorl and is present on all the 

 succeeding whorls; on the spire-whorls there are about 11, wide- 

 ly spaced ribs; these ribs are lacking from the anal fascicle, ex- 

 cept on the very earlest whorls, where they are faintly continued 

 towards the upper sutures; on the last v*^horls, the ribs are small- 

 er and number about 13; between these main ribe on the last 

 whorl there ai)pear occasionall}^ smaller and shorter ribs which 

 do not reach to the edge of the fascicle; there are 5 faint spirals 



