There was a request about the meaning/significance of the Merlion, so I did some poking around. Here's what I found out (thanks to wiki and answers sites). Turns out that it hasn't been around all that long.

A gentleman by the name of Fraser Brunner came up with the design in 1964 for the Singapore Tourism Board. It looks just like you would expect it to, a cross between a Lion's head and a Mermaid's body (Fish). It appears on souvenirs that have been approved by the Tourism Board. There are only 5 'official' Merlion statues in Singapore.

What is interesting is the story behind the design. Mr. Brunner based the design on the story of how Singapore was founded.

Singapore was founded by a Malay Prince by the name of Sang Nila Utama. He wanted to find somewhere to build a new City and set out to have a look at some islands off the coast of Sumatra. While hunting deer on one of the islands, he saw a neighboring island that had beaches "like white cloth". He was told that the island was called Temasek. He decided to go there, during the trip a bad storm blew up and the ship took on water and began to sink. They were forced to throw many things overboard. Still the ship took on water. The Prince finally threw his heavy crown overboard and the storm passed. After making it safely to the island, he went inland to do some hunting and saw a strange creature with a red body, black head and white breast. It moved with great speed and grace. He was told that it was a Lion. (though later studies of the area show that Lions were never present there and what he saw was probably a Tiger) He felt it was a very good omen and decided to build his city there. He called the city Singapura, (Singa means Lion and pura means City.) which he ruled over for close to 50 years.

Interestingly enough there is a Merlion on the 8th Marine Regiment of the US Marine Corps crest.