I started in telecommunications back when a crank on the phone had to be turned before asking the telephone operator to connect a call. The common seahorse is classified as Hippocampus hudsonius of the genus Hippocampus in the family Syngnathidae.
the extra width and length added on to the crib mattress size is to allow for drape some commercial blankets are smaller for instance at about 35 inches by 45 inches whether a smaller or larger blanket is used depends on the parents for example a larger blanket covers more of the crib but a smaller blanket is easier to pick up with the baby
I have made a lot of baby quilts for the ABC Quilt project. They range in size from 3X3 to 4X4 feet. If you want to make a quilt for the baby to drag around, this is a good size. If you want to make a quilt for the crib you might want to make it a little longer and narrower - say 3X5.