Abstract
The neogastropod family Columbellidae is a diverse cosmopolitan group of small marine snails, with its greatest diversity in the tropics. They are represented in high latitudes, but the columbellid fauna of higher latitudes tends to be much less well documented. The present paper documents the nearshore columbellid fauna of the northeastern Pacific Ocean, from the Aleutian Islands to Cedros Island, near the dividing point between Baja California and Baja California Sur. It is based on work by J.H. McLean, and completed posthumously. Examination of the regional columbellid collections in the Natural History Museum of Los Angeles County and the Santa Barbara Museum of Natural History has resulted in 24 species in eight genera, of which four new species and one new genus are described herein. The present paper focuses on dry shell material.