This month we begin a new BioMystery feature to run in each issue of American Biology Teacher throughout the year. You will find the image in the opening pages of the journal accompanied by a brief discussion located toward the back. Sometimes we'll ask a question, provide clues, change the orientation, or show only part of an organism. In all cases, it's just for fun, so we hope you enjoy this journalistic experiment. Please feel free to submit your own mystery images and perhaps we will be able to continue this feature. Let's get started with a relatively easy mystery.

What Is This?

Here is a photo of a structure from an aquatic creature. The “body” of this structure measures about 35 mms in length (not including the four trailing pieces) and is commonly found by beachcombers. What is it?