MARINE UNIVALVES 
Figure 144 represents a very graceful 
shell named Drillia penicillata, Cpr., the 
Peneciled Drill. The spire consists of 
eight slender whorls, the aperture is long, 
and the surface is smooth, brownish, 
and is marked by delicate cross-lines of 
eolor. It is found in the south. Tryon 
maintains that this species is only a vari- 
ety of D. inermis, Hds. 
Drillia torosa, Cpr., the Knobbed Drill, 
Figure 145, is found rather farther to 
the north. It is somewhat less graceful 
than its southern relative, and is smaller 
also. The surface is almost black, but each 
whorl is marked by a spiral row of lighter 
eolored knobs. 
159 
Fig. 144 
He us The third species, Drillia moésta, Cpr., the 
Doleful Drill, resembles the last, but the 
whorls have cross-ribs instead of knobs. 
It is a southern shell, and is found under stones 
between tides. Its color is brown or 
olive, and its length is one inch. <A 
variety from San Pedro is smooth, 
with fine color lines. 
Drillia empyrosia, Dall, the Burnt 
Drill, is shown somewhat enlarged in 
Migure 146. It has yellowish whorls, 
with a burnt sienna brown tint on the 
later ones, though a paler band shows 
white patches where it crosses the ribs. 
It is not found near the shore, but is 
dredged from deep water off San 
Pedro. 
Fig. 146, x 45(*) 
