DECAPODS 57 



D'. First and second abdominal segments laterally acute. Ros- 

 trum deep lanifllicornis. 



C'. First to third abdominal segments laterally rounded, not acute. 

 D. Two supraorbital spines. 



E. Rostrum longer than the remainder of the carapace and 



with a long slender tip bispinosa. 



E'. Rostrum shorter than the remainder of the carapace. 

 F. Rostrum not reaching end of antennular peduncle 



truncata. 



F'. Rostrum reaching beyond end of antennular peduncle. 

 G. Antennular scale not reaching middle of second seg- 

 ment of peduncle. 

 H. Dorsal spines all in front of middle of carapace 



sica. 

 H'. Dorsal spines continued posterior to middle of 



carapace snyderi. 



G'. Antennular scale reaching beyond middle of second 



segment of peduncle. 

 H. Dorsal spines not reaching to posterior third of 



carapace. 



J. Upper limb of rostrum gradually diminishing in 



width from the orbit to the tip . . phippsii. 



]'. Upper limb of rostrum arcuate, widest in the 



middle. 



K. Rostrum extending only to end of antennular 

 peduncle, deep, usually bifid at tip ochotensis. 

 K'. Rostrum extending nearly to end of antennal 

 scale, less deep, tip acute .... dalli. 

 H'. Dorsal spines continued to posterior third of cara- 

 pace. 

 J. Midrib of rostrum terminating in a spine which 



projects well beyond lower limb of rostrum. 

 K. Eyes large, pyriform. Spine of antennal scale 

 extending beyond lamellar portion 



liljeborgii. 



K'. Eyes of moderate size, subcylindrical. Spine 

 of antennal scale not reaching beyond lam- 

 ellar portion murdochi. 



J'. Midrib of rostrum terminating in a spine which 



does not project beyond lower limb of rostrum. 



K. Upper margin of carapace and rostrum in ? 



convex. Third abdominal segment in $ in 



profile not projecting behind fourth segment 



arcuata. 



K'. Upper margin of carapace and of rostrum in ? 

 separated by a depression. Third abdominal 

 segment in $ in profile projecting in a horn- 

 like process behind fourth segment . spina. 

 D'. One supraorbital spine. 



