Transcriptome for echiuran worm Urechis unicinctus larvae

To obtain the related genes of larval segment formation and larval settlement in echiurans, we employed the spoon worm Urechis unicinctus, an important commercial echiuran, which mainly inhabits in the coastal sediment of China, Korea, Japan and Russia. The transcriptomic data were obtained from U. unicinctus larvae stages, including late-trochophore (LT), early-segmentation larva (ES), segmentation larva (SL) and worm-shaped larva (WL), using the next-generation RNA sequencing technique.