FIQ. 4. Racks of trays for conditioning bivalves for spawning. Racks are provided
with running ma water of differoiit tomperat,ures. Constant bvol jars for warm
urid cold wutor are H W I ~ i i i upyw left corncr. Watw from these two jarn ie rnixod
in required proportionH in the smalle~r glum jure located on lower sticdf. Ultraviolet uiiit for tmatrnerrt, of water is located at right.