In 1888, Charles Paxton Zaner, a penmanship instructor, founded the "Zanerian College of Penmanship" in Columbus Ohio. A few years later, he took in Elmer Ward Bloser as a partner and the name was changed to the Zaner-Bloser Company in 1895. Although Zaner was killed in an automobile accident in 1918, the company retained the name and has remained in business to the present day and is now best known as the publisher of "Highlights" magazine for children.
(click on pictures to enlarge)
The Zaner-Bloser Company patented a unique shape for its writing instruments, including dip pens, mechanical pencils and ballpoints. Shown here are two examples with painted wood barrels on the left. The remainder are plastic.
It appears these were manufactured by Wearever.
In the 1930s, Zaner-Bloser had the Parker Pen Company manufacture pencils in the company's unique shape. Most surviving examples are in the "True Blue" or "Modernistic Blue," although catalogs of the day show them in Lapis and Black, as well. My friend Joe Nemecek has posted a copy of the ad here.