Horseshoe crabs are often used as laboratory animals by physiologists. Members of this class have a large shield that covers the cephalothorax. The compound eyes are reduced. The second pair of appendages, the pedipalps, resemble walking legs. They have a long, spike-like appendage called a telson that projects from the rear of their bodies.
Respiration is via book gills.
Animal Diversity . Brusca, R. C., and G. J. Brusca. Sponsored in part by the Interagency Education Research Initiative, the Homeland Foundation and the University of Michigan Museum of Zoology . The ADW Team gratefully acknowledges their support. For more information.