Wicksten Key to hippolytid shrimp of eastern Pacific Ocean 593 



38 Rostrum deep, shorter than carapace, eyes large Eualus macrophthalmus (Rathbun) 



Unalaska to Point Sur, California, 110-1163 m (Butler 1980). 



Rostrum slender, as long as or longer than carapace, eyes smaller 39 



39 Posterior margin of third to sixth abdominal segments armed with median dorsal spine 



Eualus barbatus (Rathbun) 



Pribilof Islands to Santa Monica Bay, California, 82-507 m (Butler 1980, Wicksten 1984). 



Posterior margin of third to sixth abdominal segments unarmed Eualus biunguis (Rathbun) 



Bering Sea to Sea of Japan and Oregon, 90-2090 m (Butler 1980). 



40 (37) Epipods on all 3 pereopods 41 



Epipods on first and sometimes second pereopods 45 



41 Rostrum with dorsal margin markedly convex over eye, 7-14 spines Eualus avinus (Rathbun) 



Pribilof Islands to Oregon, 46-642 m (Butler 1980). 



Rostrum nearly straight over eye, fewer (2-9) spines 42 



42 Rostrum not reaching second segment of antennular peduncle 43 



Rostrum reaching second segment of antennular peduncle 44 



43 Rostrum with 2-5 dorsal teeth, telson with 3-4 pair dorsolateral spines. First pereopod slender, 



merus about 5 x as long as wide Eualus pusiolus (Kr0yer) 



Bering Sea to British Columbia and Sea of Japan, Gulf of St. Lawrence to Cape Cod, northern Europe 



to Spain, 0-1381 m (Butler 1980). 



Rostrum with 1-3 dorsal teeth, telson with 3 pair dorsolateral spines. First pereopod stout, merus 



about 1.6 X as long as wide Eualus dozei (A. Milne-Edwards) 



Chile-Cape Horn, 13-300 m (Holthuis 1952). 



44 Pleuron of fourth abdominal segment with ventral spine Eualus lineatus Wicksten and Butler 



Sitka, Alaska to Gulf of California, 18-232 m (Wicksten and Butler 1983, Wicksten 1988).i^' 



Pleuron of fourth abdominal segment without spine Eualus berkeleyorum Butler 



Pribilof Islands to off Trinidad Harbor, California, 46-384 m (Butler 1980, Wicksten 1984, Jensen 

 and Armstrong 1987). 



45 (40) Normal size epipods on first and second pereopods Eualus toumsendi (Rathbun) 



Pribilof Islands to Sea of Japan and Puget Sound, 38-630 m (Butler 1980). 



Normal or reduced epipods on first pereopods, second pereopods with reduced epipods if present .... 46 



46 Most of distal part of rostrum lacking spines on dorsal margin Eualus fabricii (Kr0yer) 



Bering Sea to Sea of Japan and British Columbia, northwest Atlantic Ocean south to Massachusetts 



Bay, 4-255 m (Butler 1980). 



Distal half of rostrum with dorsal spines Eualus suckleyi (Stimpson) 



Bering Sea to Sea of Okhotsk and Grays Harbor, Washington, 11-1025 m (Butler 1980). 



47 (36) Ventral margin of fourth pleuron without spine 48 



Ventral margin of fourth pleuron with spine 59 



48 Epipod absent on third maxilliped Heptacarpus tenuissimus Holmes 



Bird Island, Alaska to Santa Catalina Island, California, 2-137 m (Butler 1980).<y> 



Epipod present on third maxilliped 49 



