Carapace smooth. Nostrum armed with 7 or 8 teeth on dorsal, and 3 or 4 (rarely 2) teeth on ventral margin; adrostral crest and groove extending as far as, or slightly ahead, of epigastric tooth; postrostral crest well developed, almost reaching posterior margin of carapace, with or without a feeble median groove; gastrofrontal crest absent; antennal crest very prominent, ending above middle of hepatic crest; gastro-orbital crest extending over posterior half, or less, of distance between hepatic spine and orbital margin; hepatic crest straight, almost horizontal, distinctly separated from base of antennal crest; fifth pereopod without exopod.