82 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Spiral sculpture between the sutures consisting of one coarse pe- 
ripheral and many fine lines. 
Fine lines 14 interrupta. 
Fine lines 20 mighelsi. 
Spiral sculpture consisting of 4 coarse and 17 fine lines . buteonis. 
BB. Sculpture very irregular and variable. The exceeding variability 
of this species, Turbonilla (Pyrgisms) winkleyi and the variety senilis 
make it impossible to seize upon any few characters to serve in this 
key. We refer to the description, pp. 90, 92 for their definition. 
AA. Axial ribs continuing over the base of the last whorl to the umbilical 
region. 
C. Spiral sculpture consisting of incised lines of equal strength between 
the sutures. 
Axial ribs on all the whorls sximneri. 
Axial ribs feeble on the later whorls whiteavesi. 
CC. Spiral sculpture consisting of incised lines of unequal strength. 
Shell large, length of a specimen of 11 whorls 13.5 mm. . . rathbimi. 
Shell medium, length of a specimen of 10 whorls 7.3 mm . cascoensis. 
Shell small, length of a specimen of 9 whorls 5.2 mm. . . edivardensis. 
Turbonilla (Pyrgiscus) verrilli new species. 
PI. 12, figs. 21, 26. 
Shell regularly broadly conic, creamy white with a .slender yellow 
band a little above the sutures. Nuclear whorls two and one half, 
depressed helicoid, scarcely at all immersed, having their axis at right 
angles to that of the succeeding turns. Post-nuclear whorls increasing 
regularly in size, ornamented with strong, well elevated axial ribs, 
which are strongest in the middle and somewhat flattened at the 
summit. They are about half as wide as the intercostal spaces and 
about 20 appear upon the 2d; 18 upon the 3d to 7th; and 21 upon the 
penultimate turn. The rather wide intercostal spaces are marked by 
very fine, crinkly axial striations and six equally strong incised spiral 
lines. Four of these lines divide the anterior half of the whorl between 
the sutures into three equal spaces, the basal one of which is at the 
periphery; the two others divide the posterior half into an equal 
number of segments, the upper one being about as far below the 
summit as it is distant from the incised line anterior to it. The color 
band occu])ies the space between the 3d and 4th lines. Periphery 
of the last whorl rounded. Base very short, almost flat, marked by 
the weak continuations of the axial ribs which vanish before reaching 
the umbilical area, and six equally strong but unequally s])aced, 
