590 Fishery Bulletin 88(3). 1990 



10 Brightly colored with pattern of bold white spots on dark background. Anterolateral margin of 



carapace angular. (Symbiotic with sea anemones or corals) Thor amboinensis Heller 



Tropical Atlantic and Indo-Pacific, Cocos Island and Panama. Sub tidal (Chace 1972; Abele and Patton 

 1976).(3) 



Camouflaged, translucent to mottled like algae. Anterolateral margin of carapace rounded. (Not 

 symbiotic with sea anemones or corals) Thor algicola Wicksten 



Gulf of California to Panama, 0-20 m (Wicksten 1987a).(^> 



11 Carpus of second pereopod with 7 segments. Flagellum of antennae not as long as body. (Color 



in life various, often camouflaged) 12 



Carpus of second pereopod with more than 7 segments. Flagellum of antenna as long as body. 



(Color in life often red striped) 69 



12 More than 1 supraorbital spine 13 



One or no supraorbital spines 20 



13 Rostrum with 3-4 supraorbital spines 14 



Rostrum with 2 supraorbital spines 15 



14 Rostrum deep, subcircular; with 10-26 mostly small dorsal spines on rostrum proper and 3-4 dorsal 



carapace spines, ventral margin of third pleuron acute or bluntly pointed 



Spirontocaris prionota (Stimpson) 



Bering Sea to SW of San Carlos Point, Baja California, 4-163 m (Butler 1980).<5' 



Rostrum moderately deep, with 1-3 large dorsal spines, truncate apex; pleuron of third somite 



rounded Spirontocaris truncata Rathbun 



Strait of Georgia to SW of San Carlos Point, Baja California, 37-92 m (Wicksten 1984). 



15 Rostrum with styliform distal projection, no process on inner surface of eyestalk. (Usually found 



on offshore soft bottoms) 16 



Rostrum without styliform distal projection, process present on inner surface of eyestalk. (Found 

 among rocks or soft bottoms) 17 



16 Distal projection of rostrum with 1 ventral spine; epipods on first and second pereopods. (Usually 



living at 150 m or less) Spirontocaris holmesi Holthuis 



Yes Bay, Alaska to San Diego, California, 24-386 m (Butler 1980).'«' 



Distal projection of rostrum without ventral spine; epipods on first pereopods only. (Usually living 



at 150 m and deeper) Spirontocaris sica Rathbun 



Restoration Bay, British Columbia to between San Benito Islands and Cedros Island, Baja Califor- 

 nia; 88-849 m (Butler 1980, Wicksten 1987b). 



17 Pleura of first to third somites ventrally acute or bluntly pointed, dactyls of third to fifth pereo- 

 pods long, slender, with acute tips Spirontocaris lamellicornis (Dana) 



Bering Sea to Santa Monica Bay, California, 3-192 m (Butler 1980, Standing 1981). 



Pleura of first to third somites broadly rounded ventrally, dactyls of third to fifth pereopods short 



and stout with bifid tips 18 



18 Body slender to moderately stout, shell thin; epipods on first and second pereopods 



Spirontocaris snyderi Rathbun 



Queen Charlotte Islands to San Cristobal Bay, Baja California, 4-141 m (Butler 1980)."' 



Body moderately stout to stout, shell thick; epipods on first to third pereopods 19 



