The CWI Cookbook

 Scallops
Beaten egg
Crushed cracker crumbs
Lard for frying

The heart is the only part used. If you buy them in the shell, boil and take out the hearts. Those sold in our markets are generally ready for frying or stewing.
Dip them in beaten egg, then in cracker-crumbs, and fry in hot lard.

Common Sense in the Household by Marion Harland, New York, 1871

Comment: Many people are suspicious nowadays of scallops, particularly those ordered in restaurants, most particularly those ordered in restaurants which come in breaded and fried forms, as rumors have circulated for years that many are not in fact scallops at all but bits of cheaper fish products (even shark fins!) punched out in circles and pawned off as high-priced shellfish. You can avoid such problems if you follow Mrs. Harland’s advice and buy them in the shell, although we will concede that this is easier said than done for those who live any distance from the shoreline to speak of. Even in her day, it seems, they were commonly sold already pre-shelled, although apparently the shark-fin story had not yet started making the rounds.