Is there something like "crescendo" for tempo??

[kharyptho84]

On the sheet, they are the same 8 eighth notes, but when I listened to the actual rendition of the music, it sounded to me as if the notes were getting longer and longer. That is, it was as if the overall speed was getting slower.  

 I know there is (de)crescendo for velocity, and the music software did gradually mae the notes louder when I added a crescendo over a group of notes. Is there something like that but for tempo? I have tried fermata, but that only works for one note, so I do not think tha omegle t is what I need.