368 PERCY SLADEN TRUST EXPEDITION 



(2) Antennule has flagella longer than stalk and third joint sub- 

 equal to second. Two spines at end of second wrist. 

 P. (F.) holmesi Nobili, 1907. 



/3. Rostrum shallow. Second wrist not nearly as long as arm. [R. = §.] 

 P. (F.) amymone de Man, 1902. 



B. No supraorbital spine. 



1. Upper edge of rostrum straight at first, though its tip may be upturned. 



, a. Rostrum without teeth below. Last two joints of antennular stalk very 

 long. [R = f.] 



P. (F.) longimanus (Dana), 1852. 



h. Rostrum with one or more teeth below. Last two joints of antennular 

 stalk usually short. 



i. Second leg unarmed. 



a. Rostrum of good depth. Second wrist long. [R. = |E|.] 

 P. (F.) americanus (Kingsley), 1878. 



)8. Rostrum rather shallow. Second wrist short. 



(1) Rostrum has three teeth below, and two behind orbit, and is 



directed straight forwards. 



(a) R. = f with additional denticle at tip. First and second legs 



outreach antennal scale. 

 P. {F.) coinpressus Borradaile, 1915. 



(b) R. =f . First and second legs do not outreach antennal scale. 



P. (F.) amethysteus (Risso), 1826. 



(2) Rostrum has one tooth below, and one behind orbit, and is 



directed somewhat downwards. [R. =-f-.] 

 P. {F.) brocketti Borradaile, 1915. 



ii. Second leg bears one or more spines. 



a. Second wrist bears three spines. One rostral tooth behind orbit. 



(1) Second arm bears four spines. Antennal scale of good breadth. 



[R.=|.] 

 P. (F.) denticulatus Nobili, 1907. 



(2) Second arm bears one spine. Antennal scale narrow. 



P. (F.) brachiatus (Stimpson), 1860. 



/S. Second wrist bears one spine. Two rostral teeth behind orbit. 



(1) Antennal scale broad, not outcurved, its distal spine not pro- 

 jecting beyond its end. Rostrum not outreaching antennular 

 stalk. [R. = f.] 

 P. (F.) rotumanus Borradaile, 1898. 



