Class Gastropoda:Our dissection species change from semester to semester, and you will be provided with a species specific drawing(s) and instructions from your TAs on your gastropod dissection.
Class Polyplacophora:Normally you will be provided with preserved specimens of Katharina tunicata for dissection. Follow the general morphology and descriptions on pg. 244 of Sherman & Sherman. Be sure to make notes and drawings for this exercise. Is the radula for this mollusc in any way different from what you found in your earlier snail dissection?
Cephalopoda:Using the dissection guide in Sherman & Sherman, identify and note the morphology of the squidLoligo (your specimen will injected in some cases to reveal the circulatory system; all specimens arepreserved).
Demonstration:Be sure to check the aquaria for living examples of marine gastropods, polyplacophorans, andthe occasional Octopus. In the case of the latter, be sure to observe the way in which chromatophoresare employed to alter colour in this cephalopod. When you get to the Crustacea in a future laboratory,compare your observations on Octopus with those made on the chromatophores of shrimps.