Chapter 12: Molluscs

Question 1

Shell’s thin, outer organic layer

Answer 1

Periostracum

Question 2

Shell’s thin, innermost calcareous layer

Answer 2

Nacreous layer

Question 3

Shell’s thick, calcareous middle layer

Answer 3

Prismatic layer

Question 4

Specialized tissue that secretes organic and inorganic components of the shell

Answer 4

Mantle

Question 5

Cavity lying between mantle and viscera
- houses comb-like molluscan gills
- serves as exit site for the excretory, digestive, and reproductive systems

Answer 5

Mantle cavity

Question 6

Comb-like molluscan gills
- purely respiratory function
- collection and sorting of food particles

Answer 6

Ctenidium (plural: ctenidia)

Question 7

Chemoreceptor/tactile receptor located adjacent to ctenidium

Answer 7

Osphradium

Question 8

System that increases efficiency of gas exchange between blood flowing within the ctenidial filaments and the water flowing over them

Answer 8

Countercurrent exchange

Question 9

“Blood cavity” comprising the blood sinuses
- serves as hydrostatic skeleton in the locomotion of some mollusks

Answer 9

Hemocoel

Question 10

Feeding structure consisting of a firm ribbon, composed of chitin and protein, along which are found numerous rows of sharp, chitinous teeth

Answer 10

Radula

Question 11

The ribbon is produced from a ___________ and is underlain by a supportive cartilage-like structure called the ___________

Answer 11

• radular sac
• odontophore

Question 12

The odontophore-radular assembly with its complex musculature

Answer 12

• Buccal mass
• Odontophore complex