The cartoon begins with Tom preparing himself with loads of ointments and lotions for a day of sunbathing at the beach. It's immediately ruined by Jerry coming along and bothering him. For a minute they do their usual chasing before Tom runs of the end of a pier and 'drowns'.

But at the bottom of the ocean (all three feet of it beneath the pier) he comes across a mermouse who also annoys him. Cue more chases, only with an underwater twist this time involving sunken ships (three feet under a pier, a swordfish and an octopus. It's a welcome break from the generic house T&J shorts are usually set in. Some nice underwater animation earns this one a 7/10.

It's very appropriate that this short was included on the disc for the Esther Williams film "Dangerous When Wet". This is because in this full-length film, Tom & Jerry appear in a fantasy sequence--swimming with Ms. Williams. So, seeing the pair frolicking about at the beach in "The Cat and the Mermouse" seems like a perfect extra for the disc.

As I mentioned above, Tom & Jerry are at the beach. Not surprisingly, they begin beating the crap out of each other. Soon, Tom falls into the sea and sees Jerry...or what he thinks is Jerry. Instead, it's a 'mermouse'--a mermaid version of a mouse. For much of the rest of the film, it's like a standard Tom & Jerry cartoon but underwater. And, like in their appearance in "Dangerous When Wet", Tom doesn't seem to have any trouble breathing under water!

Like any Tom & Jerry cartoon before they were ruined in the late 1950s (it's a long story but these later films were dreadful), the animation is top-notch--better than the Disney or Warner Brothers shorts. With wonderful backgrounds, great animations and lovely colors, it certainly looks great. As for the story, it's the usual but set in a very unusual locale--making it more enjoyable than an average film in the series. Not among their best, but quite good.