Final answer:
The statement 'The mantle cavity contains hemolymph' about the anatomy of a mollusk is false. Gastropod anatomy includes a mantle cavity that houses gills and nephridia but does not contain hemolymph.
Step-by-step explanation:
Based on Hanson's findings about marine gastropods, we can evaluate the statements given:
- Mollusks have a radula for scraping food.
- Mollusks have ventral nerve cords.
- The tissue beneath the shell is called the mantle.
- The mantle cavity contains hemolymph.
The false statement about the anatomy of a mollusk is "The mantle cavity contains hemolymph." While the mantle cavity of gastropods does enclose gills (ctenidia) and nephridia ("kidneys"), hemolymph, the blood-like fluid found in mollusks, circulates within the body but does not fill the mantle cavity.
Gastropods are known for their torsion, where the mantle and visceral mass are rotated during their development. This feature, along with the modification of the foot for crawling and the presence of a well-defined head with tentacles and eyes, are key characteristics of gastropods. In terrestrial gastropods, the mantle cavity acts as a respiratory organ similar to lungs.