Turtle Zone Area 3
From the Super Mario Wiki
At the start of the level are two large tusks above Mario, then two Aqua Kuribō and some coins surrounded by bumps. Next is a long sparkly platform Mario is able to swim and fall through, similar to the sap in Tree Zone Area 2. Mario can use it to reach coins and a ? Block containing a carrot, though there are more sharp tusks underneath. After this are a few more bumps as well as tusks which move up and down, hurting Mario if touched. After another Aqua Kuribō are more platforms Mario can fall and swim through. In this area, there is a Para-Goomba and coins underneath between tusks. The Mid-Point Bell comes just after this.
After the checkpoint are six ? Blocks, two Aqua Kuribō, two large tusks above, and a pool of water underneath with a Honebōn in it. There are then a few more Aqua Kuribō as well as Koopa Troopas, with tusks in the middle with coins between them. There is then a large pool of water with another Honebōn in it. There are tusks both above and underneath, as well as coins, a ? Block, and a Hidden Block which contains a Moneybag. Finally, there is a Para-Goomba, a Koopa Troopa, and the pipe which takes Mario to the battle with Pako.