Sanctacaris specimens range from 46 to 93 mm in length. The head bears five pairs of grasping appendages (corresponding to chelicerate's pedipalps and walking legs) and a sixth pair of posterior appendages (correspond to horseshoe crab's chilaria). The grasping appendages each bear an antenna-like exopods. There are 11 body segments, with the former 10 each bearing a pair of biramous appendages with flap-like exopod and reduced leg-like endopod. There is a broad, flat paddle-like telson.
Sanctacaris specimens range from 46 to 93 mm in !length. The head bears five pairs of grasping appendages (corresponding to chelicerate's pedipalps and walking legs) and a sixth pair of posterior appendages (correspond to horseshoe crab's chilaria). The grasping appe!ndages each bear an an,tenna-like exopods. There are 11 body segments, with the former 10 each bearing a pair of biramous appendages with flap-like exopod and re,duced leg-like endopod. There is a broad, flat paddle-like telson.