EXPLANATION OF PLATE XXI. 
SuRCULA PARVA Conrad (p. 117). 
Fia. 1. View of the only fragment which I have observed, enlarged 24 diameters. 
DRILLIA ELEGANS Emmons (p. 115). 
Fics. 2. View of a fragment which preserves only the lower volution and a half. 
3,4. Two views of a more perfect specimen, but still imperfect in the spire. 
All twice enlarged. 
DRILLIA SUBFLEXUOSA Whitf. (p. 116). 
Figs. 5, 6,7. Three views of a very perfect shell, twice enlarged. 
DRILLIA PSEUDEBURNEA Heilprin sp. (p. 114). 
Fig. 8. View of a short, broad specimen. 
10. Two views of a more slender form. 
11,12. Two views of Prof Heilprin’s type specimens. 
All figures rather more than twice the natural size. 
NEVERITA DUPLICATA Say (p. 121). 
Figs. 13, 14. Two views of a nearly entire shell, showing the usual umbilical callosity, twice natural 
size. 
15,16. Two views of another imperfect specimen having the callus extending to the upper 
margin of the lip, natural size. 
