Microscope ID help

[Reefer1978]

I am pretty sure this is dinos, but want to double / triple confirm which species. Microscope doesn't have a camera, please forgive crappy cell phone pictures.

 

[Reefer1978]

 

[Reefer1978]

I should add that they are tiny, like dust particles at 40x, last picture is 1000x.

 

[Reefer1978]

Now that I think about it it's probably tetraselmis, but why are they brown and on the sand looking like dinos?

 

[Reefer1978]

Hopefully these pics are better.

 

[taricha]

cryptomonas / rhodomonas.

These are not a dino. They are another random harmless flagellate. Something like a cryptomonas / rhodomonas.
Here they are in a couple of vids from my system, shape and movement a lot like yours:



(Close-up):