oyster
蠣 centers on the oyster, a shellfish with a rough, stony shell.
蠣 combines 虫 (insect/creature) with 厲, which likely contributes the sound. Together they denote the oyster, a shelled creature.
The left side 虫 suggests a creature, and the right side 厲 looks like a rough, stony shape. Picture a creature with a rough, stony shell: an oyster.
For レイ, imagine a ray of sunlight hitting an oyster shell: ray -> レイ, and the oyster glistens.
oyster; oyster shell
Iwagaki oyster (Crassostrea nippona)
spiny oyster (Saccostrea kegaki)
oysters cooked in the shell
fried oysters; deep-fried oysters
oyster shell lime
rice cooked together with oyster meat, etc.
raw oyster
Pacific oyster (Crassostrea gigas)
seed oyster