A coil-shaped strand of embryos known as a whorl emerges from a nudibranch in the laboratory of developmental biologist Deirdre Lyons. Image by Neville Taraporevala, an undergraduate working in Lyons' lab.
Nudibranchs are shell-less, uncoiled, gastropod molluscs with many interesting biological and behavioral features, but they are not well-understood from a developmental or functional-genomics perspective, Lyons noted.
"We recently started working with the species Berghia stephanieae, because it is easy to rear in the lab, has a two-month generation time, and produces hundreds of embryos in a single whorl," Lyons wrote. "Here, an adult hermaphrodite can be seen from the ventral, or abdominal, side, hanging from the water’s surface tension, and laying a whorl of fertilized eggs in a long strand."