First appearance of Cecil Turtle.
The title reads "Tortoise Beats Hare" even though Cecil's last name it Turtle, he is in fact a tortoise. A tortoise spends most of its time on land, where's a turtle spends most of its life in water. A tortoise shell is domed, where the turtle shell is more streamlined to create less resistance when swimming. Also their legs differ. Tortoises have thick stumpy legs made for walking. Turtles have webbing between their toes and have long claws.
This short is a take off of the Aesop fable "The Tortoise and the Hare". But even more directly, it is Tex Avery's parody of the Disney Silly Symphony, The Tortoise and the Hare (1935). Interestingly, Max Hare from the earlier Disney film is often cited as one of the inspirations behind Bugs Bunny.
Tex Avery left Warner Bros. before he could produce any new cartoons featuring Cecil. However, he introduced a similar character in 1943, Droopy. Droopy would even take some of his tricks from his slow-and-steady predecessor, such as using his relatives to help him outsmart a wolf.