A left valve of a juvenile <i>Mercenaria campechiensis</i> viewed from the top to show the lunule and umbo. This valve is from beach drift in Sanibel, Lee County, Florida
<a href="//commons.wikimedia.org/wiki/User:Invertzoo" title="User:Invertzoo">Invertzoo</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>