Dear shanks: I thought of "tome" meaning a large old book, but dictionary says etymology uncertain. The next thing tha popped into my few functional cerebral cortical neurones was "tomalley,aka tomali" the equivalent of the liver in a lobster. I have eaten it, but with no particular enjoyment.
Now I find that health authorities recommend avoiding it, because it may have mercury, dioxins,etc. in it.
"Lobster Tomalley: No Consumption. While there is no known safety considerations when it comes to eating lobster meat, consumers are advised to refrain from eating the tomalley. The tomalley is the soft, green substance found in the body cavity of the lobster. It functions as the liver and pancreas, and test results have shown the tomalley can accumulate contaminants found in the environment. "