Invert dissections

Today we dove right into practical marine invertebrate anatomy and tissue morphology, some of us for the first time after a brief lecture introduction. Monica and I dissected an oyster (species not ID’d) and Pisaster ochraceus.

It was interesting choosing the appropriate sectioning strategy to truly pick apart important anatomical structures; for the oyster we removed the mantle and then cross-sectioned the body, after first prying open the shell with a shucking knife and a large rock as a prying hammer. We were able to easily ID gills, adductor muscle, mantle, and palps before cross-sectioning the body to discover the digestive tract and large gonads, which when placed on a slide under the microscope revealed hundreds of eggs.

The sea star proved a challenge, even with some early symptoms of wasting disease (white lesions, contorted rays) it was difficult to get very far with the scissors and dissecting scalpel; at times it took the two of us to peel the spiny cover away. We did dissect one arm to find the digestive glands and bulbous ampulla (the gonads must have washed out sometime in the dissection). All in all, a challenging and very interesting exploration into the inside life of a marine invertebrate!

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