As nouns the difference between mollusk and haemocoel
is that mollusk is (us) while haemocoel is (biology) a cavity, between the organs of arthropods and mollusks, through which the blood etc circulates.
haemocoel
English
Alternative forms
*hemocoel
Noun
(
en noun)
(biology) A cavity, between the organs of arthropods and mollusks, through which the blood etc. circulates