Midterm II (Hemichordata)

Question 1

Phylum Hemichordata

Answer 1

“Half chordates”
Gill slits (like all deuterostomes)
Once included in chordates but “notochord” = evagination of their mouth cavity called stomochord
- i.e., not homologous with chordate notochord
3-part coelom (common in deuterostomes)

Question 2

Class Enteropneusta

Answer 2

Acorn worms
Around 110 spp
Solitary, exclusively marine, deposit and suspension feeders via mucus on proboscis

Question 3

Class Pterobranchia

Answer 3

• Around 30 spp
• Small, tube-dwelling, mostly colonial, all marine
• Suspension feeders via crown of tentacles with coelomic extensions (convergent with the lophophore)