232 American Seashells 



I to i^ inches in length, slightly less than half as wide; strong, heavy 

 and pure white. Last whorl with about 13 small spiral cords and about 24 

 stronger axial ribs. Where they cross, there are small, rounded beads. Outer 

 lip near the low part has a shallow notch. Inside the lip are about a dozen 

 prominent, spiral ridges. Columella with 2 low spiral ridges near the base, 

 sometimes weaker ones above. Upper parietal wall with a strong spiral cord 

 running back into the aperture. Nuclear whorls smooth, glossy, white and 

 slightly carinate. Very commonly dredged from 20 to 100 fathoms. 



Genus Engina Gray 1839 

 Engina turbinella Kiener White-spotted Engina 



Plate 25W 



Lower Florida Keys and the West Indies. 



Vs to y2 inch in length, dark purple-brown with about 10 low, white 

 knobs per whorl on the periphery. Base with 2 to 4 spiral rows of much 

 smaller white knobs. Microscopic spiral threads numerous. Aperture thick- 

 ened and constricted by 4 to 5 whitish teeth on the outer lip and by a twist 

 of the columella just above the narrow siphonal canal. Do not confuse with 

 Mitra sulcata which has several columellar plications. Common under rocks 

 at low tide. 



Genus Searlesia Harmer 191 6 

 Searlesia dira Reeve Dire Whelk 



Figure 501! 



Alaska to Monterey, California. 



I to I /4 inches in length, half as wide, with the brown aperture half the 

 length of the dark gray, fusiform shell. Outer lip thin but strong and with 

 fine serrations which extend back into the shell as small spiral threads. Colu- 

 mella arched, chocolate-brown and glossy. Whorls in spire with 9 to 1 1 low, 

 rounded axial ribs, and all of the exterior with numerous fine, unequal-sized 

 spiral threads. Siphonal canal short and slightly twisted to the left. A com- 

 mon shallow-water species commonly from northern California to the north. 



Genus Coluhraria Schumacher 18 17 

 Colubraria lanceolata Menke Arrow Dwarf Triton 



Plate 25X 



North Carolina to both sides of Florida and the West Indies. 



% to I inch in length, slender, with 7 whorls. Aperture long and nar- 

 row. Varix strong and curled back. Parietal shield elevated into a collar. 



