Comic Title: Showcase #31
Publisher: DC (National Comics Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: Mar/Apr 1961
On Sale Date: January 26, 1961 Copyright Date January 26, 1961
Source: Library of Congress, Periodicals 1961

Newsstand Date January 26, 1961
Source: Newsdealer Magazine, V15 #11

Frequency: Bi-monthly
Cover Price: $0.10
Page Count: 32
Circulation: 213000
Editor: Jack Schiff

Title: "The Sea Beasts from One Billion B.C."
Pages: 25

Feature(s):
Aquaman (of Earth-1)

Writer: Jack Miller
Artist: Nicholas Peter Cardy

Reprinted In:
Aquaman Archives Vol. 1 HC (2003)
Showcase Presents Aquaman Vol. 1 TPB (2007)

Feature Character(s)

• Aquaman (last appearance in Justice League of America #3; next appearance in Adventure Comics #282)

Supporting Character(s)

• Aqualad (last appearance in Adventure Comics #280; next appearance in Adventure Comics #282)

Villain(s)

• John Cook (no further appearances)

Other Character(s)

• Professor Richards (no further appearances)

Comments:
Chap. 2: "The Creature Army"
Chap. 3: "The Menace of the Future Fish"

Synopsis:
A huge sea monster attacks a cargo ship. Aquaman and Aqualad rescue the ship and learn from the Coast Guard that Professor Richards, a famous zoologist needs help. Aquaman visits the professor who has invented a gun which causes fish to revert to a previous evolutionary state. The gun was stolen by his assistant, John Cook. Aquaman realizes the ray created the sea monster.

While the professor works on a reversal ray, Aquaman tries to stop Cook. He and Aqualad are unable to get close to the crook because Cook sends his devolved fish after him. After several attempts Aquaman finally manages to get close enough to Cook to get the gun from him.

Using the reversal ray designed by the professor, Aquaman changes the fish back. However, the ray becomes stuck and the fish evolve into future fish. The gun is damaged beyond repair and the fish begin attacking a coastal city. Aquaman lures them back out to sea where the effect of the ray wears off. Things are back to normal, and Cook is taken into custody.