Watch List notes:

Constantine II. As Caesar, A.D. 317-337. Silvered AE3 (19.53 mm, 3.68 g, 6 h). Siscia mint, struck A.D. 321-4. CONSTANTINVS IVN NOB C, laureate head right / CAESARVM NOSTRORVM / VOT / X, legend around laurel-wreath containing vota inscription in two lines; Є SIS radiate semicircle in exergue. RIC 182; C 38; SRCV 17194. EF, surviving silvering very nearly total. 

The "dot" in the center of the reverse is an artifact of the layout of the reverse prefatory to engraving, not a deliberate part of the devices.