Lumbricus terrestris. Live lob worms sent in tubs of slightly damp soil.
Please allow 48-72 hours for dispatch.
Given that I paid over £1 per worm, I felt slightly short-changed to only get 9 worms rather than 10. The survival time didn't seem great but difficult to tell if it was due to suffering in transit or mistreatment by students! Good apart from these minor grumbles.