1. Molluscs Study Guide

2. Mollusc Characteristics • Coelom reduced • Most viscera concentrated in dorsal visceral mass • Body covered by thick mantle (epidermis) which forms a cavity • Mantle secretes calcium carbonate shell (or spicules) • Large ventral muscular foot • Radula (band of teeth in esophagus)

3. Class Bivalvia — Clams, etc. • Body and foot laterally compressed • Shell with two hinged valves • Reduced cephalization • Edges of mantle usually fused to form siphons • Radula lost • Marine and freshwater; mostly filter-feeders

4. Kingdom: Animalia     Phylum: Mollusca          Class: Pelecypoda               Order: Eulamellibranchia                    Family: Veneridae                         Genus:Venus                              Species: mercenaria

16. http://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/animals/clam.htmlhttp://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/animals/clam.html

21. Practice Slides The next few slides have no labels. Practice using the following clam dissections.

22. Clam with one shell removed and the underlying mantle still in place.

23. Internal features of the clam; the shell and mantle have been removed to show the foot and gills (ctenidia).

24. Internal anatomy of the clam, showing mouth, stomach, intestine, heart, pericardial cavity and musculature.

25. Internal features of the clam. The foot has been opened to show the digestive system and gonads.

26. Anterior end of the clam showing the stomach and digestive gland.

27. Pericardial cavity of the clam showing the heart and the intestine passing through it. The atrium of the heart is visible.

28. Internal anatomy of the clam showing the posterior region. The cavity above the gills leading to the excurrent siphon is visible.

29. View of the siphons of the clam. The incurrent is lower and the excurrent is uppermost. (WHY?) The shell on the left side has been removed.

30. Class Cephalopoda — Squid, etc. • Shell chambered (if present), reduced, or absent • Prehensile tentacles surround mouth • Mouth with radula and beak • Muscular siphon provides jet propulsion • Well developed brain, eyes • Closed circulatory system • Marine

31. Kingdom: Animalia     Phylum: Mollusca          Class: Cephalopoda               Order: Teuthida                    Family: Loliginidae                         Genus: Loligo                              Species: brevipenna

32. Notes • Arms are for prey capture and transfer of sperm to female by male. • Tentacles are for holding prey after it is captured. • The pen is the remnant of what feature of most molluscs? • What are chromatophores used for?

40. esophagus

41. Same asBranchial Heart

42. Same as Branchial Heart

43. Male Squid

44. Male Squid

45. Squid Female

46. Squid Female

47. Squid Female

48. Squid Female

49. Squid Female

50. Squid Ganglia