- Galea
- Gametogenic calcification
- ganglion
- gas-gland
- Gastral cavity
- Gastric cirri
- Gastric cross
- Gastric peduncle
- Gastric septum
- Gastric tentacles
- Gastrodermis
- Gastrovascular
- gastrovascular cavity
- Gastrovascular system
- gastrozooid
- Gates
- Genital ostium
- Genital papilla
- Germinal kinety
- gill bar
- Gill lamellae
- Gills
- Girdle fissure
- Girdles
- gizzard
- Gizzard plate
- Glabrous stripe
- Gladius
- glands
- globose
- Gn
- gnathopod
- Gnathopods I and II
- Gns
- Gonad
- Gonodendron
- Gonopalpon
- Gonophore
- gonopore
- Gonotheca
- gonozooid
- granule
- growth lines
- Gullet bladders
- Gutter
- Gutter corner
- gymnoplean tagmosis
- gyre