APA (7th ed.) Citation

(1940). Seven new species and one new genus of hydroids, mostly from Atlantic Ocean. [s.n.].

Chicago Style (17th ed.) Citation

Seven New Species and One New Genus of Hydroids, Mostly from Atlantic Ocean. [Washington]: [s.n.], 1940.

MLA (9th ed.) Citation

Seven New Species and One New Genus of Hydroids, Mostly from Atlantic Ocean. [s.n.], 1940.