70 



BULIvETlN 39 



whorls; post-nuclear whorls about 7; sculpture with strong ribs 

 and impressed spiral lines in their interspaces; the anal fasciole 

 is a constricted band about the upper 1-4 of the whorl and which 

 passing over the ends of the ribs dislocates them as in Terebra; 

 there are 11 ribs on the last whorl which commencing at the up- 

 per suture pass across the sutural fasciole but somewhat dimin- 

 ished in strength, continue across the face of the whorl in a 

 slightl}^ oblique direction to the columellar region; the summits 

 of the ribs are smooth but the interspaces are sculptured with 

 impressed lines produced by spiral bands of regular width; there 

 are 4 such bands on the spiral-whorls and about 12 on the last 

 whorl, including a few on the canal; aperture small, subellipti- 

 cal and a short twisted canal. 



Height 7.5, diameter 1,75 mm. 

 A small species of Terebroid appearance, the ends of the ribs 

 being strongly dislocated as they pass across the small anal 

 fasciole. 



Gatun Stage: Coll. 7, E sir el la River. 



Drillia limonetta, n. sp. Plate 5, figure 10 



Shell small, solid, porcellaneous; whorls about 8, coarsely 

 ribbed and polished; fasciole absent; the sculpture consists of 

 moderately strong ribs which on the spire-whorls pass suture to 

 suture but are only slightly flexed near the upper suture; on the 

 last whorl, the ribs number about 1 1 ; the last rib is much en- 

 larged and forms the outer lip; the ribs are but shortly continu- 

 ed upon the base and do not reach the canal; in addition, the 

 surface is covered with fine, irregular threads which are nearly 

 obsolete on the upper portions of the whorls but are strong on 

 the base and on the canal; aperture subelliptical with a short 

 canal, somewhat bent or excavated ventrally; anal sinus simply 

 as a vertically directed notch at the junction of the outer lip with 

 the body-whorl and is bordered by a tooth-like denticle on its in- 

 ner side. 



Length 12.25, diameter 5.00, last whorl 7.25 mm. 



