Juveniles. Found in a dried up flat-edge egg case on beach.
The two little ones on the left look like two different species. Or maybe one is just more worn than the other?
At low tide , still hinged and alive so put it back in the water.
Bed of mussels
Edit: 2-4mm. Minute hydrobe? [Added add'l photo]
SL: 10.7mm
beach, in fine drift line, east side of the Shelter Island Ferry Slip at North Haven, Suffolk County, New York
(Peconic Bay), in drift on beach slope, 0.0 low tide 26 March 2023
The eyes of the Atlantic Bay Scallop.